[CI] Run Java CI on Mac (#19757)

Why are these changes needed?
Enable Java tests on Mac CI to avoid more breakages.

Related issue number
Closes #19700

.buildkite/pipeline.macos.yml

@@ -59,13 +59,17 @@ steps:
     - if [ "$BUILDKITE_BRANCH" = "master" ]; then python .buildkite/copy_files.py --destination jars --path ./.jar/darwin; fi
 
 
-- label: ":mac: :apple: Ray C++ and Libraries"
+- label: ":mac: :apple: Ray C++, Java and Libraries"
   <<: *common
   commands:
+    - export RAY_INSTALL_JAVA=1
     - *prelude_commands
     - TORCH_VERSION=1.6 ./ci/travis/install-dependencies.sh
     - bazel test --config=ci --test_env=CI $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=-flaky,-flaky-mac,-post_wheel_build --
       //:all python/ray/serve/... python/ray/dashboard/... -rllib/... -core_worker_test
+    # clang-format is needed by java/test.sh
+    - pip install clang-format==12.0.1
+    - ./java/test.sh
     - *epilogue_commands
 
 - label: ":mac: :apple: Worker"

java/runtime/src/main/java/io/ray/runtime/util/SystemUtil.java

@@ -36,7 +36,7 @@ public class SystemUtil {
   public static boolean isProcessAlive(int pid) {
     Process process;
     try {
-      process = Runtime.getRuntime().exec(new String[] {"ps", "-p", String.valueOf(pid)});
+      process = Runtime.getRuntime().exec(new String[] {"kill", "-0", String.valueOf(pid)});
       process.waitFor();
     } catch (InterruptedException | IOException e) {
       throw new RuntimeException(e);

java/test.sh

@@ -111,7 +111,7 @@ case "${OSTYPE}" in
   darwin*) ip=$(ipconfig getifaddr en0);;
   *) echo "Can't get ip address for ${OSTYPE}"; exit 1;;
 esac
-RAY_BACKEND_LOG_LEVEL=debug ray start --head --port=6379 --redis-password=123456
+RAY_BACKEND_LOG_LEVEL=debug ray start --head --port=6379 --redis-password=123456 --node-ip-address="$ip"
 RAY_BACKEND_LOG_LEVEL=debug java -cp bazel-bin/java/all_tests_deploy.jar -Dray.address="$ip:6379"\
  -Dray.redis.password='123456' -Dray.job.code-search-path="$PWD/bazel-bin/java/all_tests_deploy.jar" io.ray.test.MultiDriverTest
 ray stop

java/test/src/main/java/io/ray/test/RayJavaLoggingTest.java

@@ -35,7 +35,7 @@ public class RayJavaLoggingTest extends BaseTest {
         Ray.actor(HeavyLoggingActor::new)
             .setJvmOptions(
                 ImmutableList.of(
-                    "-Dray.logging.max-file-size=1MB", "-Dray.logging.max-backup-files=3"))
+                    "-Dray.logging.max-file-size=1KB", "-Dray.logging.max-backup-files=3"))
             .remote();
     Assert.assertTrue(loggingActor.task(HeavyLoggingActor::log).remote().get());
     final int pid = loggingActor.task(HeavyLoggingActor::getPid).remote().get();
@@ -46,7 +46,7 @@ public class RayJavaLoggingTest extends BaseTest {
           new File(String.format("%s/java-worker-%s-%d.%d.log", currLogDir, jobId, pid, i));
       Assert.assertTrue(rotatedFile.exists());
       long fileSize = rotatedFile.length();
-      Assert.assertTrue(fileSize > 1024 * 1024 && fileSize < 1024 * (1024 + 1));
+      Assert.assertTrue(fileSize > 1024 && fileSize < 1024 * 2);
     }
   }
 }