Problems about CountDownLatch await() method?

Question

In my program CountDownLatch await () method will continue blocking program, CountDownLatch as it is written, Is a countdown latch, when the count to zero trigger three Thread execution, and prove that three when cdAnswer reduced to 0 Thread has been executed, then the Main Thread to execute, but in my program, three Thread only completes The two Main Thread was carried out, who can help me, I would be very grateful. The bottom is my program.

public class CountdownLatchTest {
    public static void main(String[] args) {
        ExecutorService service = Executors.newCachedThreadPool();
        final CountDownLatch cdOrder = new CountDownLatch(1);
        final CountDownLatch cdAnswer = new CountDownLatch(3);

        for (int i = 0; i < 3; i++) {
            Runnable runnable = new Runnable() {
                @Override
                public void run() {
                    try {
                        System.out.println("Thread" + Thread.currentThread().getName()
                                + "Wait for the command");

                        cdOrder.await();
                        System.out.println("Thread" + Thread.currentThread().getName()
                                + "received command");
                        Thread.sleep((long) (Math.random() * 10000));
                        System.out.println("Thread" + Thread.currentThread().getName()
                                + "Feedback the results");
                        cdAnswer.countDown();
                    } catch (Exception e) {
                        e.printStackTrace();
                    } finally {
                        System.out.println("To complete the order");
                        cdAnswer.countDown();

                    }
                }
            };
            service.execute(runnable);
        }
        try {
            Thread.sleep((long) (Math.random() * 10000));

            System.out.println("Thread" + Thread.currentThread().getName()
                    + "The upcoming orders");
            cdOrder.countDown();
            System.out.println("Thread" + Thread.currentThread().getName()
                    + "Sent the command, are waiting for the result");
            cdAnswer.await();
            System.out.println("Thread" + Thread.currentThread().getName()
                    + "Have received all the response. "
                    + "The results of this task has been completed");
        } catch (Exception e) {
            e.printStackTrace();
        }
        service.shutdown();

    }
}

Problem complement： This result is not what I expected, I thought this sentence ‘Have received all the response. The results of this task has been completed’will be in the final print

The picture show the result of my program.

Answer 1

This is because if you see run method of your runnable

            public void run() {
                try {
                    System.out.println("Thread"
                            + Thread.currentThread().getName()
                            + "Wait for the command");

                    cdOrder.await();
                    System.out.println("Thread"
                            + Thread.currentThread().getName()
                            + "received command");
                    Thread.sleep((long) (Math.random() * 10000));
                    System.out.println("Thread"
                            + Thread.currentThread().getName()
                            + "Feedback the results");
                    cdAnswer.countDown(); -- countdown on latch cdAnswer
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    System.out.println("To complete the order");
                    cdAnswer.countDown(); -- countdown on latch cdAnswer

                }
            }

cdAnswer.countDown(); is called twice for each runnable one in finally and one before catch clause. So for three threads countdown is called six times as a result main thread starts after 3 countdown.

Remove cdAnswer.countDown(); just above catch statement it work as expected