for (int i = 0; i < numThreads; i++) {
      Thread thread = new Thread(task);
      thread.setUncaughtExceptionHandler(
          new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread t, Throwable e) {
              exceptions.add(e);
            }
          });
      threads.add(thread);
    }
    for (Thread t : threads) {
      t.start();
    }

    executionThread = new Thread(runnable);
    executionThread.setUncaughtExceptionHandler(
        new UncaughtExceptionHandler() {
          @Override
          public void uncaughtException(Thread thread, Throwable e) {
            thrownByExecutionThread = e;
          }
        });
    executionThread.start();
  }

  private static void throwIfSet(Throwable t) throws Throwable {

    for (int i = 0; i < numThreads; i++) {
      Thread thread = new Thread(task);
      thread.setUncaughtExceptionHandler(
          new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread t, Throwable e) {
              exceptions.add(e);
            }
          });
      threads.add(thread);
    }
    for (Thread t : threads) {
      t.start();
    }