jenkins: test on both java 8 and 9

Jenkinsfile

@@ -1,20 +1,43 @@
+final String gitRepoUrl = 'git@github.com:kemitix/mon.git'
+final String mvn = "mvn --batch-mode --update-snapshots"
+
 pipeline {
     agent any
     stages {
+        stage('Prepare') {
+            steps {
+                git url: gitRepoUrl, branch: '**', credentialsId: 'github-kemitix'
+            }
+        }
         stage('Build') {
             steps {
-                checkout([
+                parallel {
-                    $class: 'GitSCM',
+                    stage('Java 8') {
-                    branches: [[name: '**']],
+                        withMaven(maven: 'maven 3.5.2', jdk: 'JDK 1.8') {
-                    doGenerateSubmoduleConfigurations: false,
+                            sh 'mvn clean install'
-                    extensions: [[$class: 'CleanBeforeCheckout']],
+                        }
-                    submoduleCfg: [],
+                    }
-                    userRemoteConfigs: [[credentialsId: 'github-kemitix', url: 'git@github.com:kemitix/mon.git']]
+                    stage('Java 9') {
-                ])
+                        withMaven(maven: 'maven 3.5.2', jdk: 'JDK 9') {
-                sh './mvnw clean install'
+                            sh 'mvn clean install'
+                        }
+                    }
+                }
+            }
+        }
+        stage('Reporting') {
+            steps {
                 junit '**/target/surefire-reports/*.xml'
                 archiveArtifacts '**/target/*.jar'
             }
         }
+        stage('Deploy') {
+            when { expression { (env.GIT_BRANCH == 'master') } }
+            steps {
+                withMaven(maven: 'maven 3.5.2', jdk: 'JDK 1.8') {
+                    sh "${mvn} deploy --activate-profiles release"
+                }
+            }
+        }
     }
 }