Create unit tests for Concurrency

[arun-gupta]

[aslakknutsen]

Rewrite current Concurrent Tests to use Concurrent Utils; CountDownLatch|CyclicBarrier instead of slow and unsafe Thread.sleep()

e.g. https://github.com/arun-gupta/javaee7-samples/blob/master/concurrency/managedexecutor/src/test/java/org/javaee7/concurrency/managedexecutor/ExecutorInjectTest.java#L72

final CountDownLatch signal = new CountDownLatch(1);
defaultExecutor.submit(new MyRunnableTask(1) {
  void run() {
    super.run();
    signal.countDown();
  }
});
Assert.assertTrue(signal.await(2000, TimeUnit.MILLISECONDS))

[arun-gupta]

Changed the tests to use CountDownLatch now. Only created unit tests for managedexecutor. Do you want to create for others ?

[aslakknutsen]

#136