Java倒计时闩锁未解锁？为什么最后一行不打印？

countDownLatch在倒计时（）之后将不会等待到零。但是程序被锁定了。最后一次打印从未输出

public static void main(String[] args) throws Exception{
    CountDownLatch countDownLatch = new CountDownLatch(1);
    countDownLatch.await();

    new Thread(new Runnable() {
        @Override
        public void run() {
            countDownLatch.countDown();
            countDownLatch.countDown();
        }
    }).start();

    System.out.println("------should print-------");
}

如果wait方法位于线程（而不是主线程）中，则它可以工作。为什么?

public static void main(String[] args) throws Exception {
    CountDownLatch countDownLatch = new CountDownLatch(1);
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                countDownLatch.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();


    new Thread(new Runnable() {
        @Override
        public void run() {
            countDownLatch.countDown();
            countDownLatch.countDown();
        }
    }).start();

    System.out.println("------should print-------");
}

在启动子线程之前，您正在调用wait（并停止线程）：

public static void main(String[] args) throws Exception{
    CountDownLatch countDownLatch = new CountDownLatch(1);

    new Thread(new Runnable() {
        @Override
        public void run() {
            countDownLatch.countDown();
            countDownLatch.countDown();
        }
    }).start();
    countDownLatch.await();
    System.out.println("------should print-------");
}

欢迎您：）如果您可以通过选择答案将线程标记为已解决，那将非常棒；）