public Object call() throws Exception {

      for (int i = 0; i < 10; i++) {
        Future<Serializable> f;
        try {
          f = client.sleep(TimeUnit.SECONDS.toMillis(2));
          client.getCurrentDate();
        } catch (Throwable throwable) {
          throw new Exception(throwable);
        }
        assertFalse(f.isDone());
      }

      return null;
    }
 @Override
 protected void tearDown() throws Exception {
   secondClient.dispose();
   super.tearDown();
 }