code: @Test public void testExecutor() throws Exception {
    ExecutorService executor=Executors.newFixedThreadPool(10);
    try {
      final List<Future<?>> results=new ArrayList<Future<?>>();
      for (int i=0; i < 100; ++i) {
        results.add(executor.submit(new Callable<Object>(){
          @Override public Object call() throws Exception {
            HttpRequest.get(url.toExternalForm() + "/race",10,SECONDS);
            return null;
          }
        }
  ));
      }
      for (    Future<?> res : results) {
        res.get();
      }
      String result=HttpRequest.get(url.toExternalForm() + "/race",10,SECONDS);
      assertEquals("100",result);
    }
    finally {
      executor.shutdown();
    }
  }
  