diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/build.sbt.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/build.sbt.mustache
index 80a53397e3a..e1c68a17514 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/build.sbt.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/build.sbt.mustache
@@ -24,6 +24,7 @@ lazy val root = (project in file(".")).
       "org.threeten" % "threetenbp" % "1.3.5" % "compile",
       {{/threetenbp}}
       "io.gsonfire" % "gson-fire" % "1.8.3" % "compile",
+      "javax.annotation" % "jsr250-api" % "1.0" % "compile",
       "junit" % "junit" % "4.12" % "test",
       "com.novocode" % "junit-interface" % "0.10" % "test"
     )
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pom.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pom.mustache
index 84b97f52c77..6ac73ccff69 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pom.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pom.mustache
@@ -284,6 +284,11 @@
             <scope>provided</scope>
         </dependency>
         {{/parcelableModel}}
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>jsr250-api</artifactId>
+            <version>${javax-annotation-version}</version>
+        </dependency>
         <!-- test dependencies -->
         <dependency>
             <groupId>junit</groupId>
@@ -297,7 +302,7 @@
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.8.3</gson-fire-version>
-        <swagger-core-version>1.5.21</swagger-core-version>
+        <swagger-core-version>1.5.22</swagger-core-version>
         <okhttp-version>3.14.2</okhttp-version>
         <gson-version>2.8.5</gson-version>
         <commons-lang3-version>3.9</commons-lang3-version>
@@ -308,6 +313,7 @@
         <threetenbp-version>1.3.8</threetenbp-version>
         {{/threetenbp}}
         <maven-plugin-version>1.0.0</maven-plugin-version>
+        <javax-annotation-version>1.0</javax-annotation-version>
         <junit-version>4.12</junit-version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
diff --git a/modules/openapi-generator/src/main/resources/Java/travis.mustache b/modules/openapi-generator/src/main/resources/Java/travis.mustache
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/modules/openapi-generator/src/main/resources/Java/travis.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/travis.mustache
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/feign/.travis.yml b/samples/client/petstore/java/feign/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/feign/.travis.yml
+++ b/samples/client/petstore/java/feign/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/feign10x/.travis.yml b/samples/client/petstore/java/feign10x/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/feign10x/.travis.yml
+++ b/samples/client/petstore/java/feign10x/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/google-api-client/.travis.yml b/samples/client/petstore/java/google-api-client/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/google-api-client/.travis.yml
+++ b/samples/client/petstore/java/google-api-client/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/jersey1/.travis.yml b/samples/client/petstore/java/jersey1/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/jersey1/.travis.yml
+++ b/samples/client/petstore/java/jersey1/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/jersey2-java6/.travis.yml b/samples/client/petstore/java/jersey2-java6/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/jersey2-java6/.travis.yml
+++ b/samples/client/petstore/java/jersey2-java6/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/jersey2-java8/.travis.yml b/samples/client/petstore/java/jersey2-java8/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/jersey2-java8/.travis.yml
+++ b/samples/client/petstore/java/jersey2-java8/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/jersey2/.travis.yml b/samples/client/petstore/java/jersey2/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/jersey2/.travis.yml
+++ b/samples/client/petstore/java/jersey2/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/.travis.yml b/samples/client/petstore/java/okhttp-gson-parcelableModel/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/.travis.yml
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/build.sbt b/samples/client/petstore/java/okhttp-gson-parcelableModel/build.sbt
index ea38e20bc43..626e3702520 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/build.sbt
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/build.sbt
@@ -17,6 +17,7 @@ lazy val root = (project in file(".")).
       "org.apache.oltu.oauth2" % "org.apache.oltu.oauth2.client" % "1.0.1",
       "org.threeten" % "threetenbp" % "1.3.5" % "compile",
       "io.gsonfire" % "gson-fire" % "1.8.3" % "compile",
+      "javax.annotation" % "jsr250-api" % "1.0" % "compile",
       "junit" % "junit" % "4.12" % "test",
       "com.novocode" % "junit-interface" % "0.10" % "test"
     )
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/pom.xml b/samples/client/petstore/java/okhttp-gson-parcelableModel/pom.xml
index 30df3d74268..4b08da3941b 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/pom.xml
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/pom.xml
@@ -242,6 +242,11 @@
             <version>4.1.1.4</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>jsr250-api</artifactId>
+            <version>${javax-annotation-version}</version>
+        </dependency>
         <!-- test dependencies -->
         <dependency>
             <groupId>junit</groupId>
@@ -255,12 +260,13 @@
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.8.3</gson-fire-version>
-        <swagger-core-version>1.5.21</swagger-core-version>
+        <swagger-core-version>1.5.22</swagger-core-version>
         <okhttp-version>3.14.2</okhttp-version>
         <gson-version>2.8.5</gson-version>
         <commons-lang3-version>3.9</commons-lang3-version>
         <threetenbp-version>1.3.8</threetenbp-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
+        <javax-annotation-version>1.0</javax-annotation-version>
         <junit-version>4.12</junit-version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
diff --git a/samples/client/petstore/java/okhttp-gson/.travis.yml b/samples/client/petstore/java/okhttp-gson/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/okhttp-gson/.travis.yml
+++ b/samples/client/petstore/java/okhttp-gson/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/okhttp-gson/build.sbt b/samples/client/petstore/java/okhttp-gson/build.sbt
index 17e9ba0e59c..1bc31c01101 100644
--- a/samples/client/petstore/java/okhttp-gson/build.sbt
+++ b/samples/client/petstore/java/okhttp-gson/build.sbt
@@ -17,6 +17,7 @@ lazy val root = (project in file(".")).
       "org.apache.oltu.oauth2" % "org.apache.oltu.oauth2.client" % "1.0.1",
       "org.threeten" % "threetenbp" % "1.3.5" % "compile",
       "io.gsonfire" % "gson-fire" % "1.8.3" % "compile",
+      "javax.annotation" % "jsr250-api" % "1.0" % "compile",
       "junit" % "junit" % "4.12" % "test",
       "com.novocode" % "junit-interface" % "0.10" % "test"
     )
diff --git a/samples/client/petstore/java/okhttp-gson/pom.xml b/samples/client/petstore/java/okhttp-gson/pom.xml
index a716cc878d7..afc09099f67 100644
--- a/samples/client/petstore/java/okhttp-gson/pom.xml
+++ b/samples/client/petstore/java/okhttp-gson/pom.xml
@@ -235,6 +235,11 @@
             <artifactId>threetenbp</artifactId>
             <version>${threetenbp-version}</version>
         </dependency>
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>jsr250-api</artifactId>
+            <version>${javax-annotation-version}</version>
+        </dependency>
         <!-- test dependencies -->
         <dependency>
             <groupId>junit</groupId>
@@ -248,12 +253,13 @@
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.8.3</gson-fire-version>
-        <swagger-core-version>1.5.21</swagger-core-version>
+        <swagger-core-version>1.5.22</swagger-core-version>
         <okhttp-version>3.14.2</okhttp-version>
         <gson-version>2.8.5</gson-version>
         <commons-lang3-version>3.9</commons-lang3-version>
         <threetenbp-version>1.3.8</threetenbp-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
+        <javax-annotation-version>1.0</javax-annotation-version>
         <junit-version>4.12</junit-version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
diff --git a/samples/client/petstore/java/rest-assured/.travis.yml b/samples/client/petstore/java/rest-assured/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/rest-assured/.travis.yml
+++ b/samples/client/petstore/java/rest-assured/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/resteasy/.travis.yml b/samples/client/petstore/java/resteasy/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/resteasy/.travis.yml
+++ b/samples/client/petstore/java/resteasy/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/resttemplate-withXml/.travis.yml b/samples/client/petstore/java/resttemplate-withXml/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/resttemplate-withXml/.travis.yml
+++ b/samples/client/petstore/java/resttemplate-withXml/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/resttemplate/.travis.yml b/samples/client/petstore/java/resttemplate/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/resttemplate/.travis.yml
+++ b/samples/client/petstore/java/resttemplate/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit/.travis.yml b/samples/client/petstore/java/retrofit/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit/.travis.yml
+++ b/samples/client/petstore/java/retrofit/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2-play24/.travis.yml b/samples/client/petstore/java/retrofit2-play24/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2-play24/.travis.yml
+++ b/samples/client/petstore/java/retrofit2-play24/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2-play25/.travis.yml b/samples/client/petstore/java/retrofit2-play25/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2-play25/.travis.yml
+++ b/samples/client/petstore/java/retrofit2-play25/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2-play26/.travis.yml b/samples/client/petstore/java/retrofit2-play26/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2-play26/.travis.yml
+++ b/samples/client/petstore/java/retrofit2-play26/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2/.travis.yml b/samples/client/petstore/java/retrofit2/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2/.travis.yml
+++ b/samples/client/petstore/java/retrofit2/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2rx/.travis.yml b/samples/client/petstore/java/retrofit2rx/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2rx/.travis.yml
+++ b/samples/client/petstore/java/retrofit2rx/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/retrofit2rx2/.travis.yml b/samples/client/petstore/java/retrofit2rx2/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/retrofit2rx2/.travis.yml
+++ b/samples/client/petstore/java/retrofit2rx2/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/vertx/.travis.yml b/samples/client/petstore/java/vertx/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/vertx/.travis.yml
+++ b/samples/client/petstore/java/vertx/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test
diff --git a/samples/client/petstore/java/webclient/.travis.yml b/samples/client/petstore/java/webclient/.travis.yml
index 80a7f2fc66c..e3bdf2af1be 100644
--- a/samples/client/petstore/java/webclient/.travis.yml
+++ b/samples/client/petstore/java/webclient/.travis.yml
@@ -1,17 +1,22 @@
 #
-# Generated by: https://openapi-generator.tech
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
 #
 language: java
 jdk:
-  - oraclejdk8
-  - oraclejdk7
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
 before_install:
   # ensure gradlew has proper permission
   - chmod a+x ./gradlew
 script:
   # test using maven
-  - mvn test
-  # uncomment below to test using gradle
-  # - gradle test
-  # uncomment below to test using sbt 
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt 
   # - sbt test