java: un-expected behaviour when using appengine testing classes (possible memory leak)

[Miroslav Genov]

Hello, 

GAE Java SDK: 1.9.36

The following test shows that LocalServiceTestHelper is creating a new thread on each setUp which is not closed on tearDown which leads to memory leak. 

@Test
public void happyPath() {
  final LocalServiceTestHelper helper = new LocalServiceTestHelper(
      new LocalSearchServiceTestConfig(),
      new LocalDatastoreServiceTestConfig().setApplyAllHighRepJobPolicy()

  );

  for (int i = 0; i < 3000000;i++) {
    helper.setUp();

    helper.tearDown();
  }
}

The following snippet is crashing with: 

java.lang.OutOfMemoryError: unable to create new native thread
	at java.lang.Thread.start0(Native Method)
	at java.lang.Thread.start(Thread.java:714)
	at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:949)
	at java.util.concurrent.ThreadPoolExecutor.ensurePrestart(ThreadPoolExecutor.java:1590)
	at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:333)
	at java.util.concurrent.ScheduledThreadPoolExecutor.scheduleWithFixedDelay(ScheduledThreadPoolExecutor.java:594)
	at com.google.appengine.api.datastore.dev.LocalDatastoreService.startInternal(LocalDatastoreService.java:593)
	at com.google.appengine.api.datastore.dev.LocalDatastoreService.access$300(LocalDatastoreService.java:146)
	at com.google.appengine.api.datastore.dev.LocalDatastoreService$2.run(LocalDatastoreService.java:582)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.google.appengine.api.datastore.dev.LocalDatastoreService.start(LocalDatastoreService.java:579)
	at com.google.appengine.tools.development.ApiProxyLocalImpl.startServices(ApiProxyLocalImpl.java:624)
	at com.google.appengine.tools.development.ApiProxyLocalImpl.access$700(ApiProxyLocalImpl.java:47)
	at com.google.appengine.tools.development.ApiProxyLocalImpl$2.run(ApiProxyLocalImpl.java:604)
	at com.google.appengine.tools.development.ApiProxyLocalImpl$2.run(ApiProxyLocalImpl.java:601)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.google.appengine.tools.development.ApiProxyLocalImpl.getService(ApiProxyLocalImpl.java:600)
	at com.google.appengine.tools.development.testing.LocalServiceTestHelper.getLocalService(LocalServiceTestHelper.java:589)
	at com.google.appengine.tools.development.testing.LocalDatastoreServiceTestConfig.getLocalDatastoreService(LocalDatastoreServiceTestConfig.java:295)
	at com.google.appengine.tools.development.testing.LocalDatastoreServiceTestConfig.tearDown(LocalDatastoreServiceTestConfig.java:289)
	at com.google.appengine.tools.development.testing.LocalServiceTestHelper.tearDownService(LocalServiceTestHelper.java:548)
	at com.google.appengine.tools.development.testing.LocalServiceTestHelper.tearDown(LocalServiceTestHelper.java:520)

[Miroslav Genov]

Already filed an issue about this at: https://code.google.com/p/googleappengine/issues/detail?id=12945&thanks=12945&ts=1462375553