diff --git a/.circleci/config.yml b/.circleci/config.yml
index 1358ee78653..bf994be945e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -141,7 +141,7 @@ commands: # a reusable command with parameters
 jobs:
   node0:
     machine:
-      image: ubuntu-2004:202201-02
+      image: ubuntu-2004:2024.01.1
     working_directory: ~/OpenAPITools/openapi-generator
     shell: /bin/bash --login
     environment:
@@ -154,7 +154,7 @@ jobs:
           nodeNo: "0"
   node1:
     machine:
-      image: ubuntu-2004:202201-02
+      image: ubuntu-2004:2024.01.1
     working_directory: ~/OpenAPITools/openapi-generator
     shell: /bin/bash --login
     environment:
@@ -167,7 +167,7 @@ jobs:
           nodeNo: "1"
   node2:
     machine:
-      image: ubuntu-2004:202201-02
+      image: ubuntu-2004:2024.01.1
     working_directory: ~/OpenAPITools/openapi-generator
     shell: /bin/bash --login
     environment:
@@ -180,7 +180,7 @@ jobs:
           nodeNo: "2"
   node3:
     machine:
-      image: ubuntu-2004:202201-02
+      image: ubuntu-2004:2024.01.1
     working_directory: ~/OpenAPITools/openapi-generator
     shell: /bin/bash --login
     environment:
diff --git a/.github/workflows/gradle-test.yaml b/.github/workflows/gradle-test.yaml
index 8923e20077b..84903ee1128 100644
--- a/.github/workflows/gradle-test.yaml
+++ b/.github/workflows/gradle-test.yaml
@@ -10,7 +10,7 @@ on:
       - 'samples/client/petstore/java/**'
       - 'samples/openapi3/client/petstore/java/**'
 env:
-  GRADLE_VERSION: 7.2
+  GRADLE_VERSION: 8.7
 
 jobs:
   build:
diff --git a/.github/workflows/samples-java-client-jdk17.yaml b/.github/workflows/samples-java-client-jdk17.yaml
index 65bdb2a3413..e91ce9ba68b 100644
--- a/.github/workflows/samples-java-client-jdk17.yaml
+++ b/.github/workflows/samples-java-client-jdk17.yaml
@@ -34,9 +34,27 @@ jobs:
           path: |
             ~/.m2
           key: ${{ runner.os }}-${{ github.job }}-${{ env.cache-name }}-${{ hashFiles('**/pom.xml') }}
+
       - name: Build with Maven
         working-directory: ${{ matrix.sample }}
         run: mvn clean package
-      - name: Build with Gradle
+
+      - name: Cache gradle dependencies
+        uses: actions/cache@v4
+        env:
+          cache-name: gradle-caches
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-${{ github.job }}-${{ env.cache-name }}-${{ hashFiles('**/*.gradle', '**/*.gradle.kts') }}
+
+      - name: Cache gradle wrapper
+        uses: actions/cache@v4
+        env:
+          cache-name: gradle-wrapper
+        with:
+          path: ~/.gradle/wrapper
+          key: ${{ runner.os }}-${{ github.job }}-${{ env.cache-name }}-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}
+
+      - name: Build
         working-directory: ${{ matrix.sample }}
-        run: gradle clean build
+        run: ./gradlew build -x test
diff --git a/CI/circle_parallel.sh b/CI/circle_parallel.sh
index 837eaa0b522..aa5e561c15b 100755
--- a/CI/circle_parallel.sh
+++ b/CI/circle_parallel.sh
@@ -110,5 +110,6 @@ else
   (cd samples/client/petstore/java/resteasy && mvn integration-test)
   (cd samples/client/petstore/java-micronaut-client && mvn integration-test)
   (cd samples/client/petstore/java/apache-httpclient && mvn integration-test)
+  (cd samples/client/petstore/java/resttemplate-jakarta && mvn integration-test)
 
 fi
diff --git a/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.jar b/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.jar and b/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.jar differ
diff --git a/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.properties.mustache b/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.properties.mustache
index ffed3a254e9..b82aa23a4f0 100644
--- a/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.properties.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/gradle-wrapper.properties.mustache
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/modules/openapi-generator/src/main/resources/Java/gradlew.bat.mustache b/modules/openapi-generator/src/main/resources/Java/gradlew.bat.mustache
index 6a68175eb70..25da30dbdee 100644
--- a/modules/openapi-generator/src/main/resources/Java/gradlew.bat.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/gradlew.bat.mustache
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/modules/openapi-generator/src/main/resources/Java/gradlew.mustache b/modules/openapi-generator/src/main/resources/Java/gradlew.mustache
index 005bcde0428..9d0ce634cb1 100755
--- a/modules/openapi-generator/src/main/resources/Java/gradlew.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/gradlew.mustache
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/modules/openapi-generator/src/main/resources/Java/maven.yml.mustache b/modules/openapi-generator/src/main/resources/Java/maven.yml.mustache
index d33c2ce5276..69ad41543b8 100644
--- a/modules/openapi-generator/src/main/resources/Java/maven.yml.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/maven.yml.mustache
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/apache-httpclient/.github/workflows/maven.yml b/samples/client/echo_api/java/apache-httpclient/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/apache-httpclient/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/apache-httpclient/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/apache-httpclient/gradlew b/samples/client/echo_api/java/apache-httpclient/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/apache-httpclient/gradlew
+++ b/samples/client/echo_api/java/apache-httpclient/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/apache-httpclient/gradlew.bat b/samples/client/echo_api/java/apache-httpclient/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/apache-httpclient/gradlew.bat
+++ b/samples/client/echo_api/java/apache-httpclient/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/feign-gson/.github/workflows/maven.yml b/samples/client/echo_api/java/feign-gson/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/feign-gson/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/feign-gson/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/feign-gson/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/feign-gson/gradlew b/samples/client/echo_api/java/feign-gson/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/feign-gson/gradlew
+++ b/samples/client/echo_api/java/feign-gson/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/feign-gson/gradlew.bat b/samples/client/echo_api/java/feign-gson/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/feign-gson/gradlew.bat
+++ b/samples/client/echo_api/java/feign-gson/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/native/.github/workflows/maven.yml b/samples/client/echo_api/java/native/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/native/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/native/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/native/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/native/gradlew b/samples/client/echo_api/java/native/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/native/gradlew
+++ b/samples/client/echo_api/java/native/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/native/gradlew.bat b/samples/client/echo_api/java/native/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/native/gradlew.bat
+++ b/samples/client/echo_api/java/native/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/.github/workflows/maven.yml b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew
+++ b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew.bat b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew.bat
+++ b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/okhttp-gson/.github/workflows/maven.yml b/samples/client/echo_api/java/okhttp-gson/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/okhttp-gson/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/okhttp-gson/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/okhttp-gson/gradlew b/samples/client/echo_api/java/okhttp-gson/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/okhttp-gson/gradlew
+++ b/samples/client/echo_api/java/okhttp-gson/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/okhttp-gson/gradlew.bat b/samples/client/echo_api/java/okhttp-gson/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/okhttp-gson/gradlew.bat
+++ b/samples/client/echo_api/java/okhttp-gson/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/resteasy/.github/workflows/maven.yml b/samples/client/echo_api/java/resteasy/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/resteasy/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/resteasy/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/resteasy/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/resteasy/gradlew b/samples/client/echo_api/java/resteasy/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/resteasy/gradlew
+++ b/samples/client/echo_api/java/resteasy/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/resteasy/gradlew.bat b/samples/client/echo_api/java/resteasy/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/resteasy/gradlew.bat
+++ b/samples/client/echo_api/java/resteasy/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/echo_api/java/resttemplate/.github/workflows/maven.yml b/samples/client/echo_api/java/resttemplate/.github/workflows/maven.yml
index 4ff479f4b4f..543a3007900 100644
--- a/samples/client/echo_api/java/resttemplate/.github/workflows/maven.yml
+++ b/samples/client/echo_api/java/resttemplate/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.jar b/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.jar and b/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.properties b/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/echo_api/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/echo_api/java/resttemplate/gradlew b/samples/client/echo_api/java/resttemplate/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/echo_api/java/resttemplate/gradlew
+++ b/samples/client/echo_api/java/resttemplate/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/echo_api/java/resttemplate/gradlew.bat b/samples/client/echo_api/java/resttemplate/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/echo_api/java/resttemplate/gradlew.bat
+++ b/samples/client/echo_api/java/resttemplate/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/jersey2-oneOf-Mixed/.github/workflows/maven.yml b/samples/client/others/java/jersey2-oneOf-Mixed/.github/workflows/maven.yml
index 1dd421c4835..16e07aa898b 100644
--- a/samples/client/others/java/jersey2-oneOf-Mixed/.github/workflows/maven.yml
+++ b/samples/client/others/java/jersey2-oneOf-Mixed/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/jersey2-oneOf-Mixed/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/jersey2-oneOf-Mixed/gradlew b/samples/client/others/java/jersey2-oneOf-Mixed/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/jersey2-oneOf-Mixed/gradlew
+++ b/samples/client/others/java/jersey2-oneOf-Mixed/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/jersey2-oneOf-Mixed/gradlew.bat b/samples/client/others/java/jersey2-oneOf-Mixed/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/jersey2-oneOf-Mixed/gradlew.bat
+++ b/samples/client/others/java/jersey2-oneOf-Mixed/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/jersey2-oneOf-duplicates/.github/workflows/maven.yml b/samples/client/others/java/jersey2-oneOf-duplicates/.github/workflows/maven.yml
index 1dd421c4835..16e07aa898b 100644
--- a/samples/client/others/java/jersey2-oneOf-duplicates/.github/workflows/maven.yml
+++ b/samples/client/others/java/jersey2-oneOf-duplicates/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/jersey2-oneOf-duplicates/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/jersey2-oneOf-duplicates/gradlew b/samples/client/others/java/jersey2-oneOf-duplicates/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/jersey2-oneOf-duplicates/gradlew
+++ b/samples/client/others/java/jersey2-oneOf-duplicates/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/jersey2-oneOf-duplicates/gradlew.bat b/samples/client/others/java/jersey2-oneOf-duplicates/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/jersey2-oneOf-duplicates/gradlew.bat
+++ b/samples/client/others/java/jersey2-oneOf-duplicates/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/okhttp-gson-oneOf/.github/workflows/maven.yml b/samples/client/others/java/okhttp-gson-oneOf/.github/workflows/maven.yml
index 1b4a533253c..08a45f321d1 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/.github/workflows/maven.yml
+++ b/samples/client/others/java/okhttp-gson-oneOf/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/okhttp-gson-oneOf/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/okhttp-gson-oneOf/gradlew b/samples/client/others/java/okhttp-gson-oneOf/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/gradlew
+++ b/samples/client/others/java/okhttp-gson-oneOf/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/okhttp-gson-oneOf/gradlew.bat b/samples/client/others/java/okhttp-gson-oneOf/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/gradlew.bat
+++ b/samples/client/others/java/okhttp-gson-oneOf/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/okhttp-gson-streaming/.github/workflows/maven.yml b/samples/client/others/java/okhttp-gson-streaming/.github/workflows/maven.yml
index 39df19de3cd..e43bb4aa033 100644
--- a/samples/client/others/java/okhttp-gson-streaming/.github/workflows/maven.yml
+++ b/samples/client/others/java/okhttp-gson-streaming/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/okhttp-gson-streaming/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/okhttp-gson-streaming/gradlew b/samples/client/others/java/okhttp-gson-streaming/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/okhttp-gson-streaming/gradlew
+++ b/samples/client/others/java/okhttp-gson-streaming/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/okhttp-gson-streaming/gradlew.bat b/samples/client/others/java/okhttp-gson-streaming/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/okhttp-gson-streaming/gradlew.bat
+++ b/samples/client/others/java/okhttp-gson-streaming/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/resttemplate-useAbstractionForFiles/.github/workflows/maven.yml b/samples/client/others/java/resttemplate-useAbstractionForFiles/.github/workflows/maven.yml
index 893d361fbd7..8b6f7a6aef0 100644
--- a/samples/client/others/java/resttemplate-useAbstractionForFiles/.github/workflows/maven.yml
+++ b/samples/client/others/java/resttemplate-useAbstractionForFiles/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew
+++ b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew.bat b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew.bat
+++ b/samples/client/others/java/resttemplate-useAbstractionForFiles/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/others/java/webclient-useAbstractionForFiles/.github/workflows/maven.yml b/samples/client/others/java/webclient-useAbstractionForFiles/.github/workflows/maven.yml
index 893d361fbd7..8b6f7a6aef0 100644
--- a/samples/client/others/java/webclient-useAbstractionForFiles/.github/workflows/maven.yml
+++ b/samples/client/others/java/webclient-useAbstractionForFiles/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar b/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar and b/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties b/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/others/java/webclient-useAbstractionForFiles/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/others/java/webclient-useAbstractionForFiles/gradlew b/samples/client/others/java/webclient-useAbstractionForFiles/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/others/java/webclient-useAbstractionForFiles/gradlew
+++ b/samples/client/others/java/webclient-useAbstractionForFiles/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/others/java/webclient-useAbstractionForFiles/gradlew.bat b/samples/client/others/java/webclient-useAbstractionForFiles/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/others/java/webclient-useAbstractionForFiles/gradlew.bat
+++ b/samples/client/others/java/webclient-useAbstractionForFiles/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/apache-httpclient/.github/workflows/maven.yml b/samples/client/petstore/java/apache-httpclient/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/apache-httpclient/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/apache-httpclient/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/apache-httpclient/gradlew b/samples/client/petstore/java/apache-httpclient/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/apache-httpclient/gradlew
+++ b/samples/client/petstore/java/apache-httpclient/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/apache-httpclient/gradlew.bat b/samples/client/petstore/java/apache-httpclient/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/apache-httpclient/gradlew.bat
+++ b/samples/client/petstore/java/apache-httpclient/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/feign-no-nullable/.github/workflows/maven.yml b/samples/client/petstore/java/feign-no-nullable/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/feign-no-nullable/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/feign-no-nullable/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/feign-no-nullable/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/feign-no-nullable/gradlew b/samples/client/petstore/java/feign-no-nullable/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/feign-no-nullable/gradlew
+++ b/samples/client/petstore/java/feign-no-nullable/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/feign-no-nullable/gradlew.bat b/samples/client/petstore/java/feign-no-nullable/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/feign-no-nullable/gradlew.bat
+++ b/samples/client/petstore/java/feign-no-nullable/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/feign/.github/workflows/maven.yml b/samples/client/petstore/java/feign/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/feign/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/feign/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/feign/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/feign/gradlew b/samples/client/petstore/java/feign/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/feign/gradlew
+++ b/samples/client/petstore/java/feign/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/feign/gradlew.bat b/samples/client/petstore/java/feign/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/feign/gradlew.bat
+++ b/samples/client/petstore/java/feign/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/google-api-client/.github/workflows/maven.yml b/samples/client/petstore/java/google-api-client/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/google-api-client/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/google-api-client/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/google-api-client/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/google-api-client/gradlew b/samples/client/petstore/java/google-api-client/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/google-api-client/gradlew
+++ b/samples/client/petstore/java/google-api-client/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/google-api-client/gradlew.bat b/samples/client/petstore/java/google-api-client/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/google-api-client/gradlew.bat
+++ b/samples/client/petstore/java/google-api-client/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/jersey2-java8-localdatetime/.github/workflows/maven.yml b/samples/client/petstore/java/jersey2-java8-localdatetime/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/jersey2-java8-localdatetime/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/jersey2-java8-localdatetime/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/jersey2-java8-localdatetime/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew b/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew
+++ b/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew.bat b/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew.bat
+++ b/samples/client/petstore/java/jersey2-java8-localdatetime/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/jersey2-java8/.github/workflows/maven.yml b/samples/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/jersey2-java8/gradlew b/samples/client/petstore/java/jersey2-java8/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/jersey2-java8/gradlew
+++ b/samples/client/petstore/java/jersey2-java8/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/jersey2-java8/gradlew.bat b/samples/client/petstore/java/jersey2-java8/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/jersey2-java8/gradlew.bat
+++ b/samples/client/petstore/java/jersey2-java8/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/jersey3/.github/workflows/maven.yml b/samples/client/petstore/java/jersey3/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/jersey3/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/jersey3/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/jersey3/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/jersey3/gradlew b/samples/client/petstore/java/jersey3/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/jersey3/gradlew
+++ b/samples/client/petstore/java/jersey3/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/jersey3/gradlew.bat b/samples/client/petstore/java/jersey3/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/jersey3/gradlew.bat
+++ b/samples/client/petstore/java/jersey3/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/native-async/.github/workflows/maven.yml b/samples/client/petstore/java/native-async/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/native-async/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/native-async/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/native-async/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/native-async/gradlew b/samples/client/petstore/java/native-async/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/native-async/gradlew
+++ b/samples/client/petstore/java/native-async/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/native-async/gradlew.bat b/samples/client/petstore/java/native-async/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/native-async/gradlew.bat
+++ b/samples/client/petstore/java/native-async/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/native-jakarta/.github/workflows/maven.yml b/samples/client/petstore/java/native-jakarta/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/native-jakarta/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/native-jakarta/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/native-jakarta/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/native-jakarta/gradlew b/samples/client/petstore/java/native-jakarta/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/native-jakarta/gradlew
+++ b/samples/client/petstore/java/native-jakarta/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/native-jakarta/gradlew.bat b/samples/client/petstore/java/native-jakarta/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/native-jakarta/gradlew.bat
+++ b/samples/client/petstore/java/native-jakarta/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/native/.github/workflows/maven.yml b/samples/client/petstore/java/native/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/native/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/native/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/native/gradlew b/samples/client/petstore/java/native/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/native/gradlew
+++ b/samples/client/petstore/java/native/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/native/gradlew.bat b/samples/client/petstore/java/native/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/native/gradlew.bat
+++ b/samples/client/petstore/java/native/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-3.1/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-3.1/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-3.1/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/gradlew b/samples/client/petstore/java/okhttp-gson-3.1/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-3.1/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/gradlew.bat b/samples/client/petstore/java/okhttp-gson-3.1/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-3.1/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-awsv4signature/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew.bat b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-dynamicOperations/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew.bat b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-group-parameter/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew b/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew.bat b/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-nullable-required/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew b/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew.bat b/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-parcelableModel/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew.bat b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-swagger1/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/gradlew b/samples/client/petstore/java/okhttp-gson-swagger1/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/gradlew.bat b/samples/client/petstore/java/okhttp-gson-swagger1/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson-swagger2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/gradlew b/samples/client/petstore/java/okhttp-gson-swagger2/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/gradlew
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/gradlew.bat b/samples/client/petstore/java/okhttp-gson-swagger2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/okhttp-gson/.github/workflows/maven.yml b/samples/client/petstore/java/okhttp-gson/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/okhttp-gson/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/okhttp-gson/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/okhttp-gson/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/okhttp-gson/gradlew b/samples/client/petstore/java/okhttp-gson/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/okhttp-gson/gradlew
+++ b/samples/client/petstore/java/okhttp-gson/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/okhttp-gson/gradlew.bat b/samples/client/petstore/java/okhttp-gson/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/okhttp-gson/gradlew.bat
+++ b/samples/client/petstore/java/okhttp-gson/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/rest-assured-jackson/.github/workflows/maven.yml b/samples/client/petstore/java/rest-assured-jackson/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/rest-assured-jackson/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/rest-assured-jackson/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/rest-assured-jackson/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/rest-assured-jackson/gradlew b/samples/client/petstore/java/rest-assured-jackson/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/rest-assured-jackson/gradlew
+++ b/samples/client/petstore/java/rest-assured-jackson/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/rest-assured-jackson/gradlew.bat b/samples/client/petstore/java/rest-assured-jackson/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/rest-assured-jackson/gradlew.bat
+++ b/samples/client/petstore/java/rest-assured-jackson/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/rest-assured/.github/workflows/maven.yml b/samples/client/petstore/java/rest-assured/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/rest-assured/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/rest-assured/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/rest-assured/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/rest-assured/gradlew b/samples/client/petstore/java/rest-assured/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/rest-assured/gradlew
+++ b/samples/client/petstore/java/rest-assured/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/rest-assured/gradlew.bat b/samples/client/petstore/java/rest-assured/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/rest-assured/gradlew.bat
+++ b/samples/client/petstore/java/rest-assured/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resteasy/.github/workflows/maven.yml b/samples/client/petstore/java/resteasy/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resteasy/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resteasy/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resteasy/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resteasy/gradlew b/samples/client/petstore/java/resteasy/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/resteasy/gradlew
+++ b/samples/client/petstore/java/resteasy/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resteasy/gradlew.bat b/samples/client/petstore/java/resteasy/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resteasy/gradlew.bat
+++ b/samples/client/petstore/java/resteasy/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resttemplate-jakarta/.github/workflows/maven.yml b/samples/client/petstore/java/resttemplate-jakarta/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resttemplate-jakarta/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resttemplate-jakarta/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resttemplate-jakarta/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resttemplate-jakarta/gradlew b/samples/client/petstore/java/resttemplate-jakarta/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/resttemplate-jakarta/gradlew
+++ b/samples/client/petstore/java/resttemplate-jakarta/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resttemplate-jakarta/gradlew.bat b/samples/client/petstore/java/resttemplate-jakarta/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resttemplate-jakarta/gradlew.bat
+++ b/samples/client/petstore/java/resttemplate-jakarta/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resttemplate-swagger1/.github/workflows/maven.yml b/samples/client/petstore/java/resttemplate-swagger1/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resttemplate-swagger1/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resttemplate-swagger1/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resttemplate-swagger1/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resttemplate-swagger1/gradlew b/samples/client/petstore/java/resttemplate-swagger1/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/resttemplate-swagger1/gradlew
+++ b/samples/client/petstore/java/resttemplate-swagger1/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resttemplate-swagger1/gradlew.bat b/samples/client/petstore/java/resttemplate-swagger1/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resttemplate-swagger1/gradlew.bat
+++ b/samples/client/petstore/java/resttemplate-swagger1/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resttemplate-swagger2/.github/workflows/maven.yml b/samples/client/petstore/java/resttemplate-swagger2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resttemplate-swagger2/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resttemplate-swagger2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resttemplate-swagger2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resttemplate-swagger2/gradlew b/samples/client/petstore/java/resttemplate-swagger2/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/resttemplate-swagger2/gradlew
+++ b/samples/client/petstore/java/resttemplate-swagger2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resttemplate-swagger2/gradlew.bat b/samples/client/petstore/java/resttemplate-swagger2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resttemplate-swagger2/gradlew.bat
+++ b/samples/client/petstore/java/resttemplate-swagger2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resttemplate-withXml/.github/workflows/maven.yml b/samples/client/petstore/java/resttemplate-withXml/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resttemplate-withXml/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resttemplate-withXml/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resttemplate-withXml/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resttemplate-withXml/gradlew b/samples/client/petstore/java/resttemplate-withXml/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/resttemplate-withXml/gradlew
+++ b/samples/client/petstore/java/resttemplate-withXml/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resttemplate-withXml/gradlew.bat b/samples/client/petstore/java/resttemplate-withXml/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resttemplate-withXml/gradlew.bat
+++ b/samples/client/petstore/java/resttemplate-withXml/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/resttemplate/.github/workflows/maven.yml b/samples/client/petstore/java/resttemplate/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/resttemplate/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/resttemplate/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/resttemplate/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/resttemplate/gradlew b/samples/client/petstore/java/resttemplate/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/resttemplate/gradlew
+++ b/samples/client/petstore/java/resttemplate/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/resttemplate/gradlew.bat b/samples/client/petstore/java/resttemplate/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/resttemplate/gradlew.bat
+++ b/samples/client/petstore/java/resttemplate/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/retrofit2-play26/.github/workflows/maven.yml b/samples/client/petstore/java/retrofit2-play26/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/retrofit2-play26/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/retrofit2-play26/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/retrofit2-play26/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/retrofit2-play26/gradlew b/samples/client/petstore/java/retrofit2-play26/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/retrofit2-play26/gradlew
+++ b/samples/client/petstore/java/retrofit2-play26/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/retrofit2-play26/gradlew.bat b/samples/client/petstore/java/retrofit2-play26/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/retrofit2-play26/gradlew.bat
+++ b/samples/client/petstore/java/retrofit2-play26/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/retrofit2/.github/workflows/maven.yml b/samples/client/petstore/java/retrofit2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/retrofit2/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/retrofit2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/retrofit2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/retrofit2/gradlew b/samples/client/petstore/java/retrofit2/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/retrofit2/gradlew
+++ b/samples/client/petstore/java/retrofit2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/retrofit2/gradlew.bat b/samples/client/petstore/java/retrofit2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/retrofit2/gradlew.bat
+++ b/samples/client/petstore/java/retrofit2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/retrofit2rx2/.github/workflows/maven.yml b/samples/client/petstore/java/retrofit2rx2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/retrofit2rx2/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/retrofit2rx2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/retrofit2rx2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/retrofit2rx2/gradlew b/samples/client/petstore/java/retrofit2rx2/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/retrofit2rx2/gradlew
+++ b/samples/client/petstore/java/retrofit2rx2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/retrofit2rx2/gradlew.bat b/samples/client/petstore/java/retrofit2rx2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/retrofit2rx2/gradlew.bat
+++ b/samples/client/petstore/java/retrofit2rx2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/retrofit2rx3/.github/workflows/maven.yml b/samples/client/petstore/java/retrofit2rx3/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/retrofit2rx3/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/retrofit2rx3/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/retrofit2rx3/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/retrofit2rx3/gradlew b/samples/client/petstore/java/retrofit2rx3/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/retrofit2rx3/gradlew
+++ b/samples/client/petstore/java/retrofit2rx3/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/retrofit2rx3/gradlew.bat b/samples/client/petstore/java/retrofit2rx3/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/retrofit2rx3/gradlew.bat
+++ b/samples/client/petstore/java/retrofit2rx3/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/vertx-no-nullable/.github/workflows/maven.yml b/samples/client/petstore/java/vertx-no-nullable/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/vertx-no-nullable/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/vertx-no-nullable/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/vertx-no-nullable/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/vertx-no-nullable/gradlew b/samples/client/petstore/java/vertx-no-nullable/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/vertx-no-nullable/gradlew
+++ b/samples/client/petstore/java/vertx-no-nullable/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/vertx-no-nullable/gradlew.bat b/samples/client/petstore/java/vertx-no-nullable/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/vertx-no-nullable/gradlew.bat
+++ b/samples/client/petstore/java/vertx-no-nullable/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/vertx/.github/workflows/maven.yml b/samples/client/petstore/java/vertx/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/vertx/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/vertx/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/vertx/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/vertx/gradlew b/samples/client/petstore/java/vertx/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/vertx/gradlew
+++ b/samples/client/petstore/java/vertx/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/vertx/gradlew.bat b/samples/client/petstore/java/vertx/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/vertx/gradlew.bat
+++ b/samples/client/petstore/java/vertx/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/webclient-jakarta/.github/workflows/maven.yml b/samples/client/petstore/java/webclient-jakarta/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/webclient-jakarta/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/webclient-jakarta/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/webclient-jakarta/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/webclient-jakarta/gradlew b/samples/client/petstore/java/webclient-jakarta/gradlew
index 005bcde0428..9d0ce634cb1 100755
--- a/samples/client/petstore/java/webclient-jakarta/gradlew
+++ b/samples/client/petstore/java/webclient-jakarta/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/webclient-jakarta/gradlew.bat b/samples/client/petstore/java/webclient-jakarta/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/webclient-jakarta/gradlew.bat
+++ b/samples/client/petstore/java/webclient-jakarta/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/webclient-nullable-arrays/.github/workflows/maven.yml b/samples/client/petstore/java/webclient-nullable-arrays/.github/workflows/maven.yml
index a7d2ed86a81..9b7c8ca8cae 100644
--- a/samples/client/petstore/java/webclient-nullable-arrays/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/webclient-nullable-arrays/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/webclient-nullable-arrays/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/webclient-nullable-arrays/gradlew b/samples/client/petstore/java/webclient-nullable-arrays/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/webclient-nullable-arrays/gradlew
+++ b/samples/client/petstore/java/webclient-nullable-arrays/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/webclient-nullable-arrays/gradlew.bat b/samples/client/petstore/java/webclient-nullable-arrays/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/webclient-nullable-arrays/gradlew.bat
+++ b/samples/client/petstore/java/webclient-nullable-arrays/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/webclient-swagger2/.github/workflows/maven.yml b/samples/client/petstore/java/webclient-swagger2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/webclient-swagger2/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/webclient-swagger2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/webclient-swagger2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/webclient-swagger2/gradlew b/samples/client/petstore/java/webclient-swagger2/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/webclient-swagger2/gradlew
+++ b/samples/client/petstore/java/webclient-swagger2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/webclient-swagger2/gradlew.bat b/samples/client/petstore/java/webclient-swagger2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/webclient-swagger2/gradlew.bat
+++ b/samples/client/petstore/java/webclient-swagger2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/java/webclient/.github/workflows/maven.yml b/samples/client/petstore/java/webclient/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/client/petstore/java/webclient/.github/workflows/maven.yml
+++ b/samples/client/petstore/java/webclient/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/webclient/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/webclient/gradlew b/samples/client/petstore/java/webclient/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/client/petstore/java/webclient/gradlew
+++ b/samples/client/petstore/java/webclient/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/java/webclient/gradlew.bat b/samples/client/petstore/java/webclient/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/client/petstore/java/webclient/gradlew.bat
+++ b/samples/client/petstore/java/webclient/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/client/petstore/ruby-autoload/Gemfile.lock b/samples/client/petstore/ruby-autoload/Gemfile.lock
new file mode 100644
index 00000000000..8e2a9aaea67
--- /dev/null
+++ b/samples/client/petstore/ruby-autoload/Gemfile.lock
@@ -0,0 +1,73 @@
+PATH
+  remote: .
+  specs:
+    petstore (1.0.0)
+      typhoeus (~> 1.0, >= 1.0.1)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    byebug (11.1.3)
+    coderay (1.1.3)
+    diff-lcs (1.5.1)
+    ethon (0.16.0)
+      ffi (>= 1.15.0)
+    ffi (1.16.3)
+    jaro_winkler (1.5.6)
+    method_source (1.1.0)
+    parallel (1.24.0)
+    parser (3.3.0.5)
+      ast (~> 2.4.1)
+      racc
+    pry (0.14.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    pry-byebug (3.10.1)
+      byebug (~> 11.0)
+      pry (>= 0.13, < 0.15)
+    psych (5.1.2)
+      stringio
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.0.6)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    rubocop (0.66.0)
+      jaro_winkler (~> 1.5.1)
+      parallel (~> 1.10)
+      parser (>= 2.5, != 2.5.1.1)
+      psych (>= 3.1.0)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 1.6)
+    ruby-progressbar (1.13.0)
+    stringio (3.1.0)
+    typhoeus (1.4.1)
+      ethon (>= 0.9.0)
+    unicode-display_width (1.5.0)
+
+PLATFORMS
+  arm64-darwin-23
+  ruby
+
+DEPENDENCIES
+  petstore!
+  pry-byebug
+  rake (~> 13.0.1)
+  rspec (~> 3.6, >= 3.6.0)
+  rubocop (~> 0.66.0)
+
+BUNDLED WITH
+   2.5.9
diff --git a/samples/client/petstore/ruby-faraday/Gemfile.lock b/samples/client/petstore/ruby-faraday/Gemfile.lock
new file mode 100644
index 00000000000..87c9dc2135a
--- /dev/null
+++ b/samples/client/petstore/ruby-faraday/Gemfile.lock
@@ -0,0 +1,81 @@
+PATH
+  remote: .
+  specs:
+    petstore (1.0.0)
+      faraday (>= 1.0.1, < 3.0)
+      faraday-multipart
+      marcel
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    byebug (11.1.3)
+    coderay (1.1.3)
+    diff-lcs (1.5.1)
+    faraday (2.9.0)
+      faraday-net_http (>= 2.0, < 3.2)
+    faraday-multipart (1.0.4)
+      multipart-post (~> 2)
+    faraday-net_http (3.1.0)
+      net-http
+    jaro_winkler (1.5.6)
+    marcel (1.0.4)
+    method_source (1.1.0)
+    multipart-post (2.4.0)
+    net-http (0.4.1)
+      uri
+    parallel (1.24.0)
+    parser (3.3.0.5)
+      ast (~> 2.4.1)
+      racc
+    pry (0.14.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    pry-byebug (3.10.1)
+      byebug (~> 11.0)
+      pry (>= 0.13, < 0.15)
+    psych (5.1.2)
+      stringio
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.0.6)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    rubocop (0.66.0)
+      jaro_winkler (~> 1.5.1)
+      parallel (~> 1.10)
+      parser (>= 2.5, != 2.5.1.1)
+      psych (>= 3.1.0)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 1.6)
+    ruby-progressbar (1.13.0)
+    stringio (3.1.0)
+    unicode-display_width (1.5.0)
+    uri (0.13.0)
+
+PLATFORMS
+  arm64-darwin-23
+  ruby
+
+DEPENDENCIES
+  petstore!
+  pry-byebug
+  rake (~> 13.0.1)
+  rspec (~> 3.6, >= 3.6.0)
+  rubocop (~> 0.66.0)
+
+BUNDLED WITH
+   2.5.9
diff --git a/samples/client/petstore/ruby-httpx/Gemfile.lock b/samples/client/petstore/ruby-httpx/Gemfile.lock
index 3093f407a24..147d4d99ef1 100644
--- a/samples/client/petstore/ruby-httpx/Gemfile.lock
+++ b/samples/client/petstore/ruby-httpx/Gemfile.lock
@@ -7,40 +7,43 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    ast (2.4.1)
+    ast (2.4.2)
     byebug (11.1.3)
     coderay (1.1.3)
-    diff-lcs (1.4.4)
-    http-2-next (1.0.0)
-    httpx (1.0.1)
-      http-2-next (>= 1.0.0)
-    jaro_winkler (1.5.4)
-    method_source (1.0.0)
-    parallel (1.19.2)
-    parser (2.7.1.5)
+    diff-lcs (1.5.1)
+    http-2-next (1.0.3)
+    httpx (1.2.4)
+      http-2-next (>= 1.0.3)
+    jaro_winkler (1.5.6)
+    method_source (1.1.0)
+    parallel (1.24.0)
+    parser (3.3.0.5)
       ast (~> 2.4.1)
-    pry (0.13.1)
+      racc
+    pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    pry-byebug (3.9.0)
+    pry-byebug (3.10.1)
       byebug (~> 11.0)
-      pry (~> 0.13.0)
-    psych (3.2.0)
-    rainbow (3.0.0)
-    rake (13.0.1)
-    rspec (3.9.0)
-      rspec-core (~> 3.9.0)
-      rspec-expectations (~> 3.9.0)
-      rspec-mocks (~> 3.9.0)
-    rspec-core (3.9.2)
-      rspec-support (~> 3.9.3)
-    rspec-expectations (3.9.2)
+      pry (>= 0.13, < 0.15)
+    psych (5.1.2)
+      stringio
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.0.6)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.9.0)
-    rspec-mocks (3.9.1)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.9.0)
-    rspec-support (3.9.3)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
     rubocop (0.66.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
@@ -49,10 +52,12 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.6)
-    ruby-progressbar (1.10.1)
+    ruby-progressbar (1.13.0)
+    stringio (3.1.0)
     unicode-display_width (1.5.0)
 
 PLATFORMS
+  arm64-darwin-23
   ruby
 
 DEPENDENCIES
@@ -63,4 +68,4 @@ DEPENDENCIES
   rubocop (~> 0.66.0)
 
 BUNDLED WITH
-   1.17.2
+   2.5.9
diff --git a/samples/client/petstore/ruby/Gemfile.lock b/samples/client/petstore/ruby/Gemfile.lock
index f6aa4f5abfe..8e2a9aaea67 100644
--- a/samples/client/petstore/ruby/Gemfile.lock
+++ b/samples/client/petstore/ruby/Gemfile.lock
@@ -7,40 +7,43 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    ast (2.4.1)
+    ast (2.4.2)
     byebug (11.1.3)
     coderay (1.1.3)
-    diff-lcs (1.4.4)
-    ethon (0.12.0)
-      ffi (>= 1.3.0)
-    ffi (1.13.1)
-    jaro_winkler (1.5.4)
-    method_source (1.0.0)
-    parallel (1.19.2)
-    parser (2.7.1.5)
+    diff-lcs (1.5.1)
+    ethon (0.16.0)
+      ffi (>= 1.15.0)
+    ffi (1.16.3)
+    jaro_winkler (1.5.6)
+    method_source (1.1.0)
+    parallel (1.24.0)
+    parser (3.3.0.5)
       ast (~> 2.4.1)
-    pry (0.13.1)
+      racc
+    pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    pry-byebug (3.9.0)
+    pry-byebug (3.10.1)
       byebug (~> 11.0)
-      pry (~> 0.13.0)
-    psych (3.2.0)
-    rainbow (3.0.0)
-    rake (13.0.1)
-    rspec (3.9.0)
-      rspec-core (~> 3.9.0)
-      rspec-expectations (~> 3.9.0)
-      rspec-mocks (~> 3.9.0)
-    rspec-core (3.9.2)
-      rspec-support (~> 3.9.3)
-    rspec-expectations (3.9.2)
+      pry (>= 0.13, < 0.15)
+    psych (5.1.2)
+      stringio
+    racc (1.7.3)
+    rainbow (3.1.1)
+    rake (13.0.6)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.9.0)
-    rspec-mocks (3.9.1)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.9.0)
-    rspec-support (3.9.3)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
     rubocop (0.66.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
@@ -49,12 +52,14 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.6)
-    ruby-progressbar (1.10.1)
-    typhoeus (1.4.0)
+    ruby-progressbar (1.13.0)
+    stringio (3.1.0)
+    typhoeus (1.4.1)
       ethon (>= 0.9.0)
     unicode-display_width (1.5.0)
 
 PLATFORMS
+  arm64-darwin-23
   ruby
 
 DEPENDENCIES
@@ -65,4 +70,4 @@ DEPENDENCIES
   rubocop (~> 0.66.0)
 
 BUNDLED WITH
-   1.17.2
+   2.5.9
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/.github/workflows/maven.yml b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/.github/workflows/maven.yml
index 9622fcc9e07..6bd3c344ba7 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/.github/workflows/maven.yml
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew.bat b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew.bat
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/java/jersey2-java8/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/.github/workflows/maven.yml b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/.github/workflows/maven.yml
index 61960dfc743..fc30e929e53 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/.github/workflows/maven.yml
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew.bat b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew.bat
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-special-characters/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/.github/workflows/maven.yml b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/.github/workflows/maven.yml
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew.bat b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew.bat
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger1/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/.github/workflows/maven.yml b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/.github/workflows/maven.yml
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew.bat b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew.bat
+++ b/samples/openapi3/client/petstore/java/jersey2-java8-swagger2/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/.github/workflows/maven.yml b/samples/openapi3/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
index 1dc4b505d7e..460f78bfd1b 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/.github/workflows/maven.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8' ]
+        java: [ 17, 21 ]
     steps:
     - uses: actions/checkout@v4
     - name: Set up JDK
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae..e6441136f3d 100644
Binary files a/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
index ffed3a254e9..b82aa23a4f0 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/gradlew b/samples/openapi3/client/petstore/java/jersey2-java8/gradlew
index 005bcde0428..9d0ce634cb1 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/gradlew
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/gradlew
@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -69,37 +69,35 @@ app_path=$0
 
 # Need this for daisy-chained symlinks.
 while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
+APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+[ -h "$app_path" ]
 do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+ls=$( ls -ld "$app_path" )
+link=${ls#*' -> '}
+case $link in             #(
+/*)   app_path=$link ;; #(
+*)    app_path=$APP_HOME$link ;;
+esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
 
 warn () {
-    echo "$*"
+echo "$*"
 } >&2
 
 die () {
-    echo
-    echo "$*"
-    echo
-    exit 1
+echo
+echo "$*"
+echo
+exit 1
 } >&2
 
 # OS specific support (must be 'true' or 'false').
@@ -108,10 +106,10 @@ msys=false
 darwin=false
 nonstop=false
 case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+CYGWIN* )         cygwin=true  ;; #(
+Darwin* )         darwin=true  ;; #(
+MSYS* | MINGW* )  msys=true    ;; #(
+NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,39 +117,46 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
-    else
-        JAVACMD=$JAVA_HOME/bin/java
-    fi
-    if [ ! -x "$JAVACMD" ] ; then
-        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
-
-Please set the JAVA_HOME variable in your environment to match the
-location of your Java installation."
-    fi
+if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+# IBM's JDK on AIX uses strange locations for the executables
+JAVACMD=$JAVA_HOME/jre/sh/java
 else
-    JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+JAVACMD=$JAVA_HOME/bin/java
+fi
+if [ ! -x "$JAVACMD" ] ; then
+die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
 fi
+else
+JAVACMD=java
+if ! command -v java >/dev/null 2>&1
+then
+die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+case $MAX_FD in #(
+max*)
+# In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+MAX_FD=$( ulimit -H -n ) ||
+warn "Could not query maximum file descriptor limit"
+esac
+case $MAX_FD in  #(
+'' | soft) :;; #(
+*)
+# In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+# shellcheck disable=SC2039,SC3045
+ulimit -n "$MAX_FD" ||
+warn "Could not set maximum file descriptor limit to $MAX_FD"
+esac
 fi
 
 # Collect all arguments for the java command, stacking in reverse order:
@@ -164,46 +169,56 @@ fi
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
-    done
+# Now convert the arguments - kludge to limit ourselves to /bin/sh
+for arg do
+if
+case $arg in                                #(
+-*)   false ;;                            # don't mess with options #(
+/?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+[ -e "$t" ] ;;                      #(
+*)    false ;;
+esac
+then
+arg=$( cygpath --path --ignore --mixed "$arg" )
+fi
+# Roll the args list around exactly as many times as the number of
+# args, so each arg winds up back in the position where it started, but
+# possibly modified.
+#
+# NB: a `for` loop captures its iteration list before it begins, so
+# changing the positional parameters here affects neither the number of
+# iterations, nor the values presented in `arg`.
+shift                   # remove old arg
+set -- "$@" "$arg"      # push replacement arg
+done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
+"-Dorg.gradle.appname=$APP_BASE_NAME" \
+-classpath "$CLASSPATH" \
+org.gradle.wrapper.GradleWrapperMain \
+"$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+die "xargs is not available"
+fi
 
 # Use "xargs" to parse quoted args.
 #
@@ -225,10 +240,10 @@ set -- \
 #
 
 eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+xargs -n1 |
+sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+tr '\n' ' '
+)" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/gradlew.bat b/samples/openapi3/client/petstore/java/jersey2-java8/gradlew.bat
index 6a68175eb70..25da30dbdee 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/gradlew.bat
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -33,20 +34,20 @@ set APP_HOME=%DIRNAME%
 for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -56,11 +57,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal