public static void main(String[] args) {
        ExecutorService executor = Executors.newFixedThreadPool(2);
        CompletionService<Integer> comp = new ExecutorCompletionService<Integer>(executor);

        Callable<Integer> task1 = new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                Thread.sleep(50);
                return 1;
            }
        };

        Callable<Integer> task2 = new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                Thread.sleep(100);
                throw new Exception("test");
            }
        };

        Future<Integer> future1 = comp.submit(task1);
        Future<Integer> future2 = comp.submit(task2);

        try {
            System.out.println(comp.take().get());
            System.out.println(comp.take().get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }


        executor.shutdown();
    }