Setup build matrix for OpenJDK 8, 9 and 11 on Circle CI

.circleci/config.yml

@@ -1,28 +1,51 @@
+gbsteps: &gbsteps
+  steps:
+    - run:
+        name: Report on build environment
+        command: |
+          java -version
+          javac -version
+
+    - checkout
+    - run: ant
+
+    - run: ant test
+    - run:
+        name: Collect test results
+        command: |
+          mkdir -p test_reports/junit/
+          cp -a build/tests/TEST-*.xml test_reports/junit/
+    - store_test_results:
+        path: test_reports
+    - store_artifacts:
+        path:  build/target/reports
+
+
 version: 2
 
 jobs:
-  build:
+  buildJ8:
     docker:
       - image: circleci/openjdk:8-jdk
 
-    steps:
-      - run:
-          name: Report on build environment
-          command: |
-            java -version
-            javac -version
-
-      - checkout
-      - run: ant
-
-      - run: ant test
-      - run:
-          name: Collect test results
-          command: |
-            mkdir -p test_reports/junit/
-            cp -a build/tests/TEST-*.xml test_reports/junit/
-      - store_test_results:
-          path: test_reports
-      - store_artifacts:
-          path:  build/target/reports
+    <<: *gbsteps
+
+  buildJ9:
+    docker:
+      - image: circleci/openjdk:9-jdk
+
+    <<: *gbsteps
+
+  buildJ11:
+    docker:
+      - image: circleci/openjdk:11-jdk
+
+    <<: *gbsteps
 
+workflows:
+  version: 2
+  build:
+    jobs:
+      - "buildJ8"
+      - "buildJ9"
+      - "buildJ11"