Merge pull request #7 from apache/gm/jdk-12

Add test for JDK 12
diff --git a/Jenkinsfile.sample b/Jenkinsfile.sample
index 7862bcc..075e155 100644
--- a/Jenkinsfile.sample
+++ b/Jenkinsfile.sample
@@ -20,6 +20,8 @@
 try {
         
 node('ubuntu') {
+        def JAVA_JDK_12=tool name: 'JDK 12 (latest)', type: 'hudson.model.JDK'
+        echo "Testing with Java $JAVA_JDK_12"
         def JAVA_JDK_11=tool name: 'JDK 11 (latest)', type: 'hudson.model.JDK'
         echo "Testing with Java $JAVA_JDK_11"      
         def JAVA_JDK_9=tool name: 'JDK 1.9 (latest)', type: 'hudson.model.JDK'
@@ -37,6 +39,13 @@
         def ANT_LATEST=tool name: 'Ant (latest)', type: 'hudson.tasks.Ant$AntInstallation'
         echo "Testing with Ant $ANT_LATEST"
         
+        stage('JAVA 12 (Latest) on Ubuntu'){
+        withEnv(["Path+JDK=$JAVA_JDK_12/bin","JAVA_HOME=$JAVA_JDK_12"]) {
+                sh "java -version"
+                sh "javac -version"
+                }
+        } //end stage JAVA 12
+        
         stage('JAVA 11 (Latest) on Ubuntu'){
         withEnv(["Path+JDK=$JAVA_JDK_11/bin","JAVA_HOME=$JAVA_JDK_11"]) {
                 sh "java -version"