Add CI check that checks formatting of Java sources

It uses google-java-format 1.9.

Fixes #1170.

Author: PhilippWendler

.gitlab-ci.yml

@@ -108,6 +108,15 @@ java:
   tags:
     - privileged
 
+java-format:
+  stage: checks
+  image: openjdk:11
+  script: "java/check-format.sh"
+  cache:
+    key: "$CI_JOB_NAME"
+    paths:
+      - "java/*.jar"
+
 .build-docker:
   image:
     name: gcr.io/kaniko-project/executor:debug

.travis.yml

@@ -9,6 +9,7 @@ env:
     - NAME="gcc-5" DOCKER_IMAGE=registry.gitlab.com/sosy-lab/software/sv-benchmarks/ci/gcc:5 COMMAND="gcc-5 -v --version; cd c; ./diff_ci.sh 'make -j2 CC=gcc-5 -C'"
     - NAME="clang-3.9" DOCKER_IMAGE=registry.gitlab.com/sosy-lab/software/sv-benchmarks/ci/clang:3.9 COMMAND="clang-3.9 -v --version; cd c; ./diff_ci.sh 'make -j2 CC=clang-3.9 -C'"
     - NAME="java" DOCKER_IMAGE=registry.gitlab.com/sosy-lab/software/sv-benchmarks/ci/java COMMAND="java/check-compile.sh"
+    - NAME="java-format" DOCKER_IMAGE=openjdk:11 COMMAND="java/check-format.sh"
 
 # Hint to TravisCI that we want to use their container infrastructure
 sudo: required

java/check-format.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -eu
+shopt -s globstar
+
+GJF_VERSION="1.9"
+GJF_FILE="$(dirname "$0")/google-java-format-${GJF_VERSION}-all-deps.jar"
+
+[ -f "${GJF_FILE}" ] || wget "https://github.com/google/google-java-format/releases/download/google-java-format-${GJF_VERSION}/$(basename "${GJF_FILE}")" -O "${GJF_FILE}"
+
+echo "List of files that need to be reformatted with google-java-format ${GJF_VERSION}:"
+exec java -jar "${GJF_FILE}" --dry-run --set-exit-if-changed "$(dirname "$0")/"**/*.java