}
    CyclicBarrier barrier =
        new CyclicBarrier(
            6 // for the setter threads
                + 50 // for the listeners
                + 50 // for the blocking get threads,
                + 1); // for the main thread
    ExecutorService executor = newFixedThreadPool(barrier.getParties());

      CyclicBarrier barrier = new CyclicBarrier(numThreads + 1);
      Runnable wrapper =
          () -> {
            awaitUnchecked(barrier);
            task.run();
            awaitUnchecked(barrier);
          };
      for (int j = 0; j < 10; j++) {
        executor.execute(wrapper);
      }
      barrier.await(); // release the threads!
      barrier.await(); // wait for them all to complete

      barrier.await(1, SECONDS);
      executor.execute(barrierTask);
      // timeout means the second task wasn't even tried
      barrier.await(1, SECONDS);
    } finally {
      service.shutdown();
    }
  }

  public void testRejectedExecutionThrownWithMultipleCalls() throws Exception {
    CountDownLatch latch = new CountDownLatch(1);
    SettableFuture<?> future = SettableFuture.create();

      barrier.await(1, SECONDS);
      executor.execute(barrierTask);
      // timeout means the second task wasn't even tried
      barrier.await(1, SECONDS);
    } finally {
      service.shutdown();
    }
  }

  public void testRejectedExecutionThrownWithMultipleCalls() throws Exception {
    CountDownLatch latch = new CountDownLatch(1);
    SettableFuture<?> future = SettableFuture.create();

    }
    CyclicBarrier barrier =
        new CyclicBarrier(
            6 // for the setter threads
                + 50 // for the listeners
                + 50 // for the blocking get threads,
                + 1); // for the main thread
    ExecutorService executor = newFixedThreadPool(barrier.getParties());

    ExecutorService executor = newDirectExecutorService();
    CyclicBarrier barrier = new CyclicBarrier(2);

    FutureTask<@Nullable Void> otherTask =
        new FutureTask<>(
            () -> {
              Future<?> future =
                  executor.submit(
                      () -> {
                        // WAIT #1
                        barrier.await(1, SECONDS);

                        // WAIT #2

    ExecutorService executor = newFixedThreadPool(threadCount);
    CyclicBarrier barrier = new CyclicBarrier(threadCount);
    ImmutableList.Builder<Future<?>> futures = ImmutableList.builder();
    for (int i = 0; i < threadCount; i++) {
      futures.add(
          executor.submit(
              () -> {
                barrier.await();
                Integer first = graph.nodes().iterator().next();

    ExecutorService executor = newDirectExecutorService();
    CyclicBarrier barrier = new CyclicBarrier(2);

    FutureTask<@Nullable Void> otherTask =
        new FutureTask<>(
            () -> {
              Future<?> future =
                  executor.submit(
                      () -> {
                        // WAIT #1
                        barrier.await(1, SECONDS);

                        // WAIT #2

    ExecutorService executor = newFixedThreadPool(threadCount);
    CyclicBarrier barrier = new CyclicBarrier(threadCount);
    ImmutableList.Builder<Future<?>> futures = ImmutableList.builder();
    for (int i = 0; i < threadCount; i++) {
      futures.add(
          executor.submit(
              () -> {
                barrier.await();
                Integer first = graph.nodes().iterator().next();

* Traiter des données :
    * Par exemple, si vous recevez un fichier qui doit passer par un traitement lent, vous pouvez retourner une réponse « Accepted » (HTTP 202) puis faire le traitement en arrière-plan.

## Utiliser `BackgroundTasks` { #using-backgroundtasks }