diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/feign/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/feign/build.gradle.mustache
index 93944f967e21..3ce02e7a06e8 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/feign/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/feign/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+                artifactId = '{{artifactId}}'
+                from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/build.gradle.mustache
index 766ddb5c52db..b705c38ff8d1 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -83,7 +82,7 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     {{#java8}}
     sourceCompatibility = JavaVersion.VERSION_1_8
@@ -94,9 +93,12 @@ if(hasProperty('target') && target == 'android') {
     targetCompatibility = JavaVersion.VERSION_1_7
     {{/java8}}
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+                artifactId = '{{artifactId}}'
+                from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/build.gradle.mustache
index 46d8966d4310..03d303d0dfbf 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/build.gradle.mustache
@@ -6,18 +6,16 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_11
 targetCompatibility = JavaVersion.VERSION_11
@@ -33,9 +31,12 @@ javadoc {
     options.encoding = 'UTF-8'
 }
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = '{{artifactId}}'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = '{{artifactId}}'
+            from components.java
+        }
     }
 }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/build.gradle.mustache
index a1db459b5aec..2294f8808f2b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/resteasy/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/resteasy/build.gradle.mustache
index 67083a02010e..d43c2b7874b6 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/resteasy/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/resteasy/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,13 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
+
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/build.gradle.mustache
index 43c5845302c8..c915f08bb2a7 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -83,7 +82,7 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     {{#java8}}
     sourceCompatibility = JavaVersion.VERSION_1_8
@@ -94,9 +93,12 @@ if(hasProperty('target') && target == 'android') {
     targetCompatibility = JavaVersion.VERSION_1_7
     {{/java8}}
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit/build.gradle.mustache
index 34d66a2d5304..1266cde37cc3 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -83,14 +82,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/build.gradle.mustache
index fe9207df02d6..bb1ca7c917bf 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -83,7 +82,7 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     {{#java8}}
     sourceCompatibility = JavaVersion.VERSION_1_8
@@ -94,9 +93,12 @@ if(hasProperty('target') && target == 'android') {
     targetCompatibility = JavaVersion.VERSION_1_7
     {{/java8}}
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/vertx/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/vertx/build.gradle.mustache
index 1fce1c6262c9..bd45198caa86 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/vertx/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/vertx/build.gradle.mustache
@@ -5,19 +5,21 @@ group = '{{groupId}}'
 version = '{{artifactVersion}}'
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_1_8
 targetCompatibility = JavaVersion.VERSION_1_8
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = '{{artifactId}}'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = '{{artifactId}}'
+            from components.java
+        }
     }
 }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/webclient/build.gradle.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/webclient/build.gradle.mustache
index d419eb4010d7..08917cfd9093 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/webclient/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/webclient/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,8 +15,7 @@ buildscript {
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 if(hasProperty('target') && target == 'android') {
@@ -84,7 +82,7 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     {{#java8}}
     sourceCompatibility = JavaVersion.VERSION_1_8
@@ -95,9 +93,12 @@ if(hasProperty('target') && target == 'android') {
     targetCompatibility = JavaVersion.VERSION_1_7
     {{/java8}}
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
index 69c162d7b6f9..699361be13fd 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "{{groupId}}"
 version = "{{artifactVersion}}"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/modules/openapi-generator/src/main/resources/scala-httpclient/build.gradle.mustache b/modules/openapi-generator/src/main/resources/scala-httpclient/build.gradle.mustache
index 2ad0d4a0de00..93a6adbe1b81 100644
--- a/modules/openapi-generator/src/main/resources/scala-httpclient/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-httpclient/build.gradle.mustache
@@ -6,7 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -15,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +77,17 @@ if(hasProperty('target') && target == 'android') {
 
     apply plugin: 'scala'
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/modules/openapi-generator/src/test/resources/2_0/templates/Java/libraries/jersey2/build.gradle.mustache b/modules/openapi-generator/src/test/resources/2_0/templates/Java/libraries/jersey2/build.gradle.mustache
index 95c49396bfa4..cff97a389dc4 100644
--- a/modules/openapi-generator/src/test/resources/2_0/templates/Java/libraries/jersey2/build.gradle.mustache
+++ b/modules/openapi-generator/src/test/resources/2_0/templates/Java/libraries/jersey2/build.gradle.mustache
@@ -6,8 +6,7 @@ version = '{{artifactVersion}}'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -83,7 +82,7 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
     {{#java8}}
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
@@ -93,9 +92,12 @@ if(hasProperty('target') && target == 'android') {
     targetCompatibility = JavaVersion.VERSION_1_7
     {{/java8}}
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = '{{artifactId}}'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = '{{artifactId}}'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/feign-no-nullable/build.gradle b/samples/client/petstore/java/feign-no-nullable/build.gradle
index e8630f875ec2..2231ca517ba1 100644
--- a/samples/client/petstore/java/feign-no-nullable/build.gradle
+++ b/samples/client/petstore/java/feign-no-nullable/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-feign-no-nullable'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+                artifactId = 'petstore-feign-no-nullable'
+                from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/feign-no-nullable/gradlew b/samples/client/petstore/java/feign-no-nullable/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/feign/build.gradle b/samples/client/petstore/java/feign/build.gradle
index 6a9e84819fcf..8cbc10e5c132 100644
--- a/samples/client/petstore/java/feign/build.gradle
+++ b/samples/client/petstore/java/feign/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-feign'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+                artifactId = 'petstore-feign'
+                from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/feign/feign10x/build.gradle b/samples/client/petstore/java/feign/feign10x/build.gradle
index 68f46df20fd9..e934a53d289b 100644
--- a/samples/client/petstore/java/feign/feign10x/build.gradle
+++ b/samples/client/petstore/java/feign/feign10x/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,18 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-feign-10x'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-feign-10x'
+
+               from components.java
+            }
         }
     }
 
@@ -107,19 +110,19 @@ ext {
 }
 
 dependencies {
-    compile "io.swagger:swagger-annotations:$swagger_annotations_version"
-    compile "com.google.code.findbugs:jsr305:3.0.2"
-    compile "io.github.openfeign:feign-core:$feign_version"
-    compile "io.github.openfeign:feign-jackson:$feign_version"
-    compile "io.github.openfeign:feign-slf4j:$feign_version"
-    compile "io.github.openfeign.form:feign-form:$feign_form_version"
-    compile "com.fasterxml.jackson.core:jackson-core:$jackson_version"
-    compile "com.fasterxml.jackson.core:jackson-annotations:$jackson_version"
-    compile "com.fasterxml.jackson.core:jackson-databind:$jackson_databind_version"
-    compile "org.openapitools:jackson-databind-nullable:$jackson_databind_nullable_version"
-    compile "com.github.joschi.jackson:jackson-datatype-threetenbp:$jackson_threetenbp_version"
-    compile "org.apache.oltu.oauth2:org.apache.oltu.oauth2.client:$oltu_version"
-    compile "com.brsanthu:migbase64:2.2"
-    compile 'javax.annotation:javax.annotation-api:1.3.2'
-    testCompile "junit:junit:$junit_version"
+    compileOnly "io.swagger:swagger-annotations:$swagger_annotations_version"
+    compileOnly "com.google.code.findbugs:jsr305:3.0.2"
+    compileOnly "io.github.openfeign:feign-core:$feign_version"
+    compileOnly "io.github.openfeign:feign-jackson:$feign_version"
+    compileOnly "io.github.openfeign:feign-slf4j:$feign_version"
+    compileOnly "io.github.openfeign.form:feign-form:$feign_form_version"
+    compileOnly "com.fasterxml.jackson.core:jackson-core:$jackson_version"
+    compileOnly "com.fasterxml.jackson.core:jackson-annotations:$jackson_version"
+    compileOnly "com.fasterxml.jackson.core:jackson-databind:$jackson_databind_version"
+    compileOnly "org.openapitools:jackson-databind-nullable:$jackson_databind_nullable_version"
+    compileOnly "com.github.joschi.jackson:jackson-datatype-threetenbp:$jackson_threetenbp_version"
+    compileOnly "org.apache.oltu.oauth2:org.apache.oltu.oauth2.client:$oltu_version"
+    compileOnly "com.brsanthu:migbase64:2.2"
+    compileOnly 'javax.annotation:javax.annotation-api:1.3.2'
+    testCompileOnly "junit:junit:$junit_version"
 }
diff --git a/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.jar
index cc4fdc293d0e..7454180f2ae8 100644
Binary files a/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.properties
index 94920145f34e..ffed3a254e91 100644
--- a/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/java/feign/feign10x/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/java/feign/feign10x/gradlew b/samples/client/petstore/java/feign/feign10x/gradlew
old mode 100644
new mode 100755
index 2fe81a7d95e4..1b6c787337ff
--- a/samples/client/petstore/java/feign/feign10x/gradlew
+++ b/samples/client/petstore/java/feign/feign10x/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,78 +17,113 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       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
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+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" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
+APP_BASE_NAME=${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='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 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="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -97,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    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.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -105,79 +140,95 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=`expr $i + 1`
-    done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+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
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# 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" )
+
+    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
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$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/feign10x/gradlew.bat b/samples/client/petstore/java/feign/feign10x/gradlew.bat
index 9618d8d9607c..107acd32c4e6 100644
--- a/samples/client/petstore/java/feign/feign10x/gradlew.bat
+++ b/samples/client/petstore/java/feign/feign10x/gradlew.bat
@@ -29,6 +29,9 @@ if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+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="-Xmx64m" "-Xms64m"
 
@@ -37,7 +40,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -51,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -61,28 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/samples/client/petstore/java/feign/gradlew b/samples/client/petstore/java/feign/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/google-api-client/build.gradle b/samples/client/petstore/java/google-api-client/build.gradle
index 39ed02a1cd43..6b3f54f81662 100644
--- a/samples/client/petstore/java/google-api-client/build.gradle
+++ b/samples/client/petstore/java/google-api-client/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-google-api-client'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+                artifactId = 'petstore-google-api-client'
+                from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/google-api-client/gradlew b/samples/client/petstore/java/google-api-client/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/native-async/build.gradle b/samples/client/petstore/java/native-async/build.gradle
index 6bebeffcdd45..916539c686be 100644
--- a/samples/client/petstore/java/native-async/build.gradle
+++ b/samples/client/petstore/java/native-async/build.gradle
@@ -6,18 +6,16 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_11
 targetCompatibility = JavaVersion.VERSION_11
@@ -33,9 +31,12 @@ javadoc {
     options.encoding = 'UTF-8'
 }
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = 'petstore-native'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = 'petstore-native'
+            from components.java
+        }
     }
 }
 
diff --git a/samples/client/petstore/java/native-async/gradlew b/samples/client/petstore/java/native-async/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/native/build.gradle b/samples/client/petstore/java/native/build.gradle
index 6bebeffcdd45..916539c686be 100644
--- a/samples/client/petstore/java/native/build.gradle
+++ b/samples/client/petstore/java/native/build.gradle
@@ -6,18 +6,16 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_11
 targetCompatibility = JavaVersion.VERSION_11
@@ -33,9 +31,12 @@ javadoc {
     options.encoding = 'UTF-8'
 }
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = 'petstore-native'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = 'petstore-native'
+            from components.java
+        }
     }
 }
 
diff --git a/samples/client/petstore/java/native/gradlew b/samples/client/petstore/java/native/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/rest-assured-jackson/build.gradle b/samples/client/petstore/java/rest-assured-jackson/build.gradle
index 126452afdc1b..e99cf39b1197 100644
--- a/samples/client/petstore/java/rest-assured-jackson/build.gradle
+++ b/samples/client/petstore/java/rest-assured-jackson/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-rest-assured-jackson'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-rest-assured-jackson'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/rest-assured-jackson/gradlew b/samples/client/petstore/java/rest-assured-jackson/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/rest-assured/build.gradle b/samples/client/petstore/java/rest-assured/build.gradle
index 928f5dd49187..2c13b6f32cb7 100644
--- a/samples/client/petstore/java/rest-assured/build.gradle
+++ b/samples/client/petstore/java/rest-assured/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-rest-assured'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-rest-assured'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/rest-assured/gradlew b/samples/client/petstore/java/rest-assured/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/resteasy/build.gradle b/samples/client/petstore/java/resteasy/build.gradle
index 49838b21fe2a..c794b8613bac 100644
--- a/samples/client/petstore/java/resteasy/build.gradle
+++ b/samples/client/petstore/java/resteasy/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,13 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
+
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-resteasy'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-resteasy'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/resteasy/gradlew b/samples/client/petstore/java/resteasy/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/resttemplate-withXml/build.gradle b/samples/client/petstore/java/resttemplate-withXml/build.gradle
index 7e3a6d9dd836..f07930b7b5d2 100644
--- a/samples/client/petstore/java/resttemplate-withXml/build.gradle
+++ b/samples/client/petstore/java/resttemplate-withXml/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-resttemplate-withxml'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-resttemplate-withxml'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/resttemplate-withXml/gradlew b/samples/client/petstore/java/resttemplate-withXml/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/resttemplate/build.gradle b/samples/client/petstore/java/resttemplate/build.gradle
index d5e355df0649..a5719c67de5b 100644
--- a/samples/client/petstore/java/resttemplate/build.gradle
+++ b/samples/client/petstore/java/resttemplate/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-resttemplate'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-resttemplate'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/resttemplate/gradlew b/samples/client/petstore/java/resttemplate/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/retrofit2-play26/build.gradle b/samples/client/petstore/java/retrofit2-play26/build.gradle
index eb0580bd8c26..a34a42718477 100644
--- a/samples/client/petstore/java/retrofit2-play26/build.gradle
+++ b/samples/client/petstore/java/retrofit2-play26/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-java-client-retrofit2-play26'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-java-client-retrofit2-play26'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/retrofit2-play26/gradlew b/samples/client/petstore/java/retrofit2-play26/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/retrofit2/build.gradle b/samples/client/petstore/java/retrofit2/build.gradle
index 4dafb81ae670..8a5e2ab91c4c 100644
--- a/samples/client/petstore/java/retrofit2/build.gradle
+++ b/samples/client/petstore/java/retrofit2/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-retrofit2'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-retrofit2'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/retrofit2/gradlew b/samples/client/petstore/java/retrofit2/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/retrofit2rx2/build.gradle b/samples/client/petstore/java/retrofit2rx2/build.gradle
index 4c801b8e23d7..3fe39eddae0f 100644
--- a/samples/client/petstore/java/retrofit2rx2/build.gradle
+++ b/samples/client/petstore/java/retrofit2rx2/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-retrofit2-rx2'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-retrofit2-rx2'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/retrofit2rx2/gradlew b/samples/client/petstore/java/retrofit2rx2/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/retrofit2rx3/build.gradle b/samples/client/petstore/java/retrofit2rx3/build.gradle
index 96760ecfecc2..c1ed0c63156e 100644
--- a/samples/client/petstore/java/retrofit2rx3/build.gradle
+++ b/samples/client/petstore/java/retrofit2rx3/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-retrofit2-rx3'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-retrofit2-rx3'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/retrofit2rx3/gradlew b/samples/client/petstore/java/retrofit2rx3/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/vertx-no-nullable/build.gradle b/samples/client/petstore/java/vertx-no-nullable/build.gradle
index ef71d28b6902..220dccd2c311 100644
--- a/samples/client/petstore/java/vertx-no-nullable/build.gradle
+++ b/samples/client/petstore/java/vertx-no-nullable/build.gradle
@@ -5,19 +5,21 @@ group = 'org.openapitools'
 version = '1.0.0'
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_1_8
 targetCompatibility = JavaVersion.VERSION_1_8
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = 'petstore-vertx-no-nullable'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = 'petstore-vertx-no-nullable'
+            from components.java
+        }
     }
 }
 
diff --git a/samples/client/petstore/java/vertx-no-nullable/gradlew b/samples/client/petstore/java/vertx-no-nullable/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/vertx/build.gradle b/samples/client/petstore/java/vertx/build.gradle
index 7d499745c83a..c067ccdc2adf 100644
--- a/samples/client/petstore/java/vertx/build.gradle
+++ b/samples/client/petstore/java/vertx/build.gradle
@@ -5,19 +5,21 @@ group = 'org.openapitools'
 version = '1.0.0'
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_1_8
 targetCompatibility = JavaVersion.VERSION_1_8
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = 'petstore-vertx'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = 'petstore-vertx'
+            from components.java
+        }
     }
 }
 
diff --git a/samples/client/petstore/java/vertx/gradlew b/samples/client/petstore/java/vertx/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/webclient-nulable-arrays/build.gradle b/samples/client/petstore/java/webclient-nulable-arrays/build.gradle
index 686f85f5ace9..6cbf60d744c8 100644
--- a/samples/client/petstore/java/webclient-nulable-arrays/build.gradle
+++ b/samples/client/petstore/java/webclient-nulable-arrays/build.gradle
@@ -6,8 +6,7 @@ version = 'v1'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,8 +15,7 @@ buildscript {
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 if(hasProperty('target') && target == 'android') {
@@ -78,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-webclient-nullable-arrays'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-webclient-nullable-arrays'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/webclient-nulable-arrays/gradlew b/samples/client/petstore/java/webclient-nulable-arrays/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/java/webclient/build.gradle b/samples/client/petstore/java/webclient/build.gradle
index eb34d7a99cc5..4d1f7d9b7f4c 100644
--- a/samples/client/petstore/java/webclient/build.gradle
+++ b/samples/client/petstore/java/webclient/build.gradle
@@ -6,8 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.+'
@@ -16,8 +15,7 @@ buildscript {
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 if(hasProperty('target') && target == 'android') {
@@ -78,14 +76,17 @@ if(hasProperty('target') && target == 'android') {
 } else {
 
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'petstore-webclient'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'petstore-webclient'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/java/webclient/gradlew b/samples/client/petstore/java/webclient/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/scala-httpclient-deprecated/build.gradle b/samples/client/petstore/scala-httpclient-deprecated/build.gradle
index 90b3353edf69..db9df898b645 100644
--- a/samples/client/petstore/scala-httpclient-deprecated/build.gradle
+++ b/samples/client/petstore/scala-httpclient-deprecated/build.gradle
@@ -6,7 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -15,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -77,14 +77,17 @@ if(hasProperty('target') && target == 'android') {
 
     apply plugin: 'scala'
     apply plugin: 'java'
-    apply plugin: 'maven'
+    apply plugin: 'maven-publish'
 
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
 
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'scala-legacy-petstore'
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'scala-legacy-petstore'
+               from components.java
+            }
         }
     }
 
diff --git a/samples/client/petstore/scala-httpclient-deprecated/gradlew b/samples/client/petstore/scala-httpclient-deprecated/gradlew
old mode 100644
new mode 100755
diff --git a/samples/client/petstore/scala-httpclient/build.gradle b/samples/client/petstore/scala-httpclient/build.gradle
index bdfd125549b5..6df69a6b5b76 100644
--- a/samples/client/petstore/scala-httpclient/build.gradle
+++ b/samples/client/petstore/scala-httpclient/build.gradle
@@ -6,7 +6,7 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.5.+'
@@ -15,7 +15,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 
@@ -23,7 +23,7 @@ if(hasProperty('target') && target == 'android') {
 
     apply plugin: 'com.android.library'
     apply plugin: 'com.github.dcendents.android-maven'
-    
+
     android {
         compileSdkVersion 23
         buildToolsVersion '23.0.2'
@@ -35,7 +35,7 @@ if(hasProperty('target') && target == 'android') {
             sourceCompatibility JavaVersion.VERSION_1_7
             targetCompatibility JavaVersion.VERSION_1_7
         }
-    
+
         // Rename the aar correctly
         libraryVariants.all { variant ->
             variant.outputs.each { output ->
@@ -51,7 +51,7 @@ if(hasProperty('target') && target == 'android') {
             provided 'javax.annotation:jsr250-api:1.0'
         }
     }
-    
+
     afterEvaluate {
         android.libraryVariants.all { variant ->
             def task = project.tasks.create "jar${variant.name.capitalize()}", Jar
@@ -63,12 +63,12 @@ if(hasProperty('target') && target == 'android') {
             artifacts.add('archives', task);
         }
     }
-    
+
     task sourcesJar(type: Jar) {
         from android.sourceSets.main.java.srcDirs
         classifier = 'sources'
     }
-    
+
     artifacts {
         archives sourcesJar
     }
@@ -77,17 +77,20 @@ if(hasProperty('target') && target == 'android') {
 
     apply plugin: 'scala'
     apply plugin: 'java'
-    apply plugin: 'maven'
-    
+    apply plugin: 'maven-publish'
+
     sourceCompatibility = JavaVersion.VERSION_1_7
     targetCompatibility = JavaVersion.VERSION_1_7
-    
-    install {
-        repositories.mavenInstaller {
-            pom.artifactId = 'openapi-scala-client'
+
+    publishing {
+        publications {
+            maven(MavenPublication) {
+               artifactId = 'openapi-scala-client'
+               from components.java
+            }
         }
     }
-    
+
     task execute(type:JavaExec) {
        main = System.getProperty('mainClass')
        classpath = sourceSets.main.runtimeClasspath
@@ -113,15 +116,15 @@ repositories {
 }
 
 dependencies {
-    compile "com.fasterxml.jackson.module:jackson-module-scala_2.10:$jackson_version"
-    compile "com.sun.jersey:jersey-client:$jersey_version"
-    compile "com.sun.jersey.contribs:jersey-multipart:$jersey_version"
-    compile "org.jfarcand:jersey-ahc-client:$jersey_async_version"
-    compile "org.scala-lang:scala-library:$scala_version"
-    compile "io.swagger:swagger-core:$swagger_core_version"
-    testCompile "org.scalatest:scalatest_2.10:$scala_test_version"
-    testCompile "junit:junit:$junit_version"
-    compile "joda-time:joda-time:$jodatime_version"
-    compile "org.joda:joda-convert:$joda_version"
-    compile "com.wordnik.swagger:swagger-async-httpclient_2.10:$swagger_async_httpclient_version"
+    compileOnly "com.fasterxml.jackson.module:jackson-module-scala_2.10:$jackson_version"
+    compileOnly "com.sun.jersey:jersey-client:$jersey_version"
+    compileOnly "com.sun.jersey.contribs:jersey-multipart:$jersey_version"
+    compileOnly "org.jfarcand:jersey-ahc-client:$jersey_async_version"
+    compileOnly "org.scala-lang:scala-library:$scala_version"
+    compileOnly "io.swagger:swagger-core:$swagger_core_version"
+    testCompileOnly "org.scalatest:scalatest_2.10:$scala_test_version"
+    testCompileOnly "junit:junit:$junit_version"
+    compileOnly "joda-time:joda-time:$jodatime_version"
+    compileOnly "org.joda:joda-convert:$joda_version"
+    compileOnly "com.wordnik.swagger:swagger-async-httpclient_2.10:$swagger_async_httpclient_version"
 }
diff --git a/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.jar b/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.jar
index 87b738cbd051..7454180f2ae8 100644
Binary files a/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.jar and b/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.properties b/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.properties
index e496c054f693..ffed3a254e91 100644
--- a/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/client/petstore/scala-httpclient/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/client/petstore/scala-httpclient/gradlew b/samples/client/petstore/scala-httpclient/gradlew
index af6708ff229f..1b6c787337ff 100755
--- a/samples/client/petstore/scala-httpclient/gradlew
+++ b/samples/client/petstore/scala-httpclient/gradlew
@@ -1,78 +1,129 @@
-#!/usr/bin/env sh
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       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
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+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" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
+APP_BASE_NAME=${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='"-Xmx64m"'
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 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="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -81,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    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.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -89,84 +140,95 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=$((i+1))
-    done
-    case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+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
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=$(save "$@")
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# 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" )
 
-# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
-if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
-  cd "$(dirname "$0")"
+    JAVACMD=$( 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
 fi
 
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
 exec "$JAVACMD" "$@"
diff --git a/samples/client/petstore/scala-httpclient/gradlew.bat b/samples/client/petstore/scala-httpclient/gradlew.bat
index f9553162f122..107acd32c4e6 100644
--- a/samples/client/petstore/scala-httpclient/gradlew.bat
+++ b/samples/client/petstore/scala-httpclient/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -13,15 +29,18 @@ if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+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=
+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 init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -35,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -45,28 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/samples/openapi3/client/petstore/java/native/build.gradle b/samples/openapi3/client/petstore/java/native/build.gradle
index 2979e384fef5..a5b272d239de 100644
--- a/samples/openapi3/client/petstore/java/native/build.gradle
+++ b/samples/openapi3/client/petstore/java/native/build.gradle
@@ -6,18 +6,16 @@ version = '1.0.0'
 
 buildscript {
     repositories {
-        maven { url "https://repo1.maven.org/maven2" }
-        jcenter()
+        mavenCentral()
     }
 }
 
 repositories {
-    maven { url "https://repo1.maven.org/maven2" }
-    jcenter()
+    mavenCentral()
 }
 
 apply plugin: 'java'
-apply plugin: 'maven'
+apply plugin: 'maven-publish'
 
 sourceCompatibility = JavaVersion.VERSION_11
 targetCompatibility = JavaVersion.VERSION_11
@@ -33,9 +31,12 @@ javadoc {
     options.encoding = 'UTF-8'
 }
 
-install {
-    repositories.mavenInstaller {
-        pom.artifactId = 'petstore-openapi3-native'
+publishing {
+    publications {
+        maven(MavenPublication) {
+            artifactId = 'petstore-openapi3-native'
+            from components.java
+        }
     }
 }
 
diff --git a/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar
index e708b1c023ec..7454180f2ae8 100644
Binary files a/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
index 4d9ca1649142..ffed3a254e91 100644
--- a/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/java/native/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/samples/openapi3/client/petstore/java/native/gradlew b/samples/openapi3/client/petstore/java/native/gradlew
old mode 100644
new mode 100755
index 4f906e0c811f..1b6c787337ff
--- a/samples/openapi3/client/petstore/java/native/gradlew
+++ b/samples/openapi3/client/petstore/java/native/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,67 +17,101 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       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
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+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" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
+APP_BASE_NAME=${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='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -87,9 +121,9 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 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="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    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.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -106,80 +140,95 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=`expr $i + 1`
-    done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+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
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# 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" )
+
+    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
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/kotlin-multiplatform/build.gradle b/samples/openapi3/client/petstore/kotlin-multiplatform/build.gradle
index 47045bb577e1..6e41c14fece0 100644
--- a/samples/openapi3/client/petstore/kotlin-multiplatform/build.gradle
+++ b/samples/openapi3/client/petstore/kotlin-multiplatform/build.gradle
@@ -14,7 +14,7 @@ ext {
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.50" // $kotlin_version
@@ -23,7 +23,7 @@ buildscript {
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 kotlin {
diff --git a/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.jar b/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.jar
index 2c6137b87896..7454180f2ae8 100644
Binary files a/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.jar and b/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.properties b/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.properties
index ce3ca77db54b..ffed3a254e91 100644
--- a/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.properties
+++ b/samples/openapi3/client/petstore/kotlin-multiplatform/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Tue May 17 23:08:05 CST 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-bin.zip
diff --git a/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew b/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew
old mode 100644
new mode 100755
index 9d82f7891513..1b6c787337ff
--- a/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew
+++ b/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew
@@ -1,74 +1,129 @@
-#!/usr/bin/env bash
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       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
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+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" ]
+do
+    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"
-APP_BASE_NAME=`basename "$0"`
+APP_BASE_NAME=${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='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
-warn ( ) {
+warn () {
     echo "$*"
-}
+} >&2
 
-die ( ) {
+die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
-# Attempt to set APP_HOME
-# Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
-done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
-
 CLASSPATH=$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="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -77,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    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.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -85,76 +140,95 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=$((i+1))
-    done
-    case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+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
 fi
 
-# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
-function splitJvmOpts() {
-    JVM_OPTS=("$@")
-}
-eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
-JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+# 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" )
+
+    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
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew.bat b/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew.bat
index 5f192121eb4f..107acd32c4e6 100644
--- a/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew.bat
+++ b/samples/openapi3/client/petstore/kotlin-multiplatform/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -8,20 +24,23 @@
 @rem Set local scope for the variables with windows NT shell
 if "%OS%"=="Windows_NT" setlocal
 
-@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=
-
 set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+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="-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 init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -35,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -45,34 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-if "%@eval[2+2]" == "4" goto 4NT_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-goto execute
-
-:4NT_args
-@rem Get arguments from the 4NT Shell from JP Software
-set CMD_LINE_ARGS=%$
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/samples/openapi3/server/petstore/kotlin-springboot-reactive/build.gradle.kts b/samples/openapi3/server/petstore/kotlin-springboot-reactive/build.gradle.kts
index 682bfec8aa13..46cdd62a58fb 100644
--- a/samples/openapi3/server/petstore/kotlin-springboot-reactive/build.gradle.kts
+++ b/samples/openapi3/server/petstore/kotlin-springboot-reactive/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/samples/openapi3/server/petstore/kotlin-springboot/build.gradle.kts b/samples/openapi3/server/petstore/kotlin-springboot/build.gradle.kts
index 49fe9400f70d..2b99799bd532 100644
--- a/samples/openapi3/server/petstore/kotlin-springboot/build.gradle.kts
+++ b/samples/openapi3/server/petstore/kotlin-springboot/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts b/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
index d0e767d84cd3..ea7f93398da9 100644
--- a/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts b/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
index 49fe9400f70d..2b99799bd532 100644
--- a/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts b/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
index 24ed63f61f82..2f35ba0681d3 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {
diff --git a/samples/server/petstore/kotlin-springboot/build.gradle.kts b/samples/server/petstore/kotlin-springboot/build.gradle.kts
index d0e767d84cd3..ea7f93398da9 100644
--- a/samples/server/petstore/kotlin-springboot/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot/build.gradle.kts
@@ -2,8 +2,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     repositories {
-        jcenter()
-        maven { url = uri("https://repo1.maven.org/maven2") }
+        mavenCentral()
     }
     dependencies {
         classpath("org.springframework.boot:spring-boot-gradle-plugin:2.2.0.M3")
@@ -14,8 +13,7 @@ group = "org.openapitools"
 version = "1.0.0"
 
 repositories {
-    jcenter()
-    maven { url = uri("https://repo1.maven.org/maven2") }
+    mavenCentral()
 }
 
 tasks.withType<KotlinCompile> {