Migrate to Circle CI version 2

The new Circle CI requires a completely different configuration.

.circleci/config.yml

@@ -0,0 +1,28 @@
+version: 2
+
+jobs:
+  build:
+    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
+

circle.yml

@@ -1,22 +0,0 @@
-machine:
-  java:
-    version: openjdk7
-
-compile:
-  pre:
-    - java -version
-    - javac -version
-  override:
-    - ant
-
-test:
-  override:
-    - ant test
-  post:
-    - mkdir -p $CIRCLE_TEST_REPORTS/junit/
-    - cp -a build/tests/TEST-*.xml $CIRCLE_TEST_REPORTS/junit/
-
-general:
-  artifacts:
-    - "build/target/reports"
-