当在一个类中的匿名类中实现多个可运行接口时，java无法确定CountDownLatch为何不起作用

Question

如果我定义了一个类Team，并在该类中实现了两个runnable interfaces，那么在程序中team1和team2的任务就不会结束。然而，如果我直接在类中实现runnable，就像在WorkerOne中一样，我会在WorkerOne结束时到达打印任务的行。我不明白为什么team1和team2的任务从未完成，应用程序也没有停止。我已经在下面的控制台输出中包含了代码。我会感激你的任何想法。谢谢

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

class WorkerOne implements Runnable {
    private CountDownLatch latch;

    public WorkerOne(CountDownLatch latch) {
        this.latch = latch;
    }

    @Override
    public void run() {
        System.out
                .println("[Tasks by WorkerOne : ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + " START");
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        latch.countDown();
        System.out.println("[Tasks by WorkerOne : ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + " END");

    }

}

class Team {
    private CountDownLatch latch;

    Runnable team1 = new Runnable() {
        public void run() {
            System.out.println("[Tasks by team1: ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + "START");
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            latch.countDown();
            System.out.println("[Tasks by team1 : ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + " END");

        }
    };

    Runnable team2 = new Runnable() {
        public void run() {
            System.out.println("[Tasks by team2 : ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + "START");
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            latch.countDown();
            System.out.println("[Tasks by team2 : ]" + " :: " + "[" + Thread.currentThread().getName() + "]" + " END");

        }
    };
}

public class Demo {

    public static void main(String[] args) {
        CountDownLatch latch = new CountDownLatch(3);
        ExecutorService service = Executors.newFixedThreadPool(3);
        service.submit(new WorkerOne(latch));
        service.submit(new Team().team1);
        service.submit(new Team().team2);
        try {
            latch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Tasks completed......");
    }
}

控制台输出为：

[Tasks by WorkerOne : ] :: [pool-1-thread-1] START
[Tasks by team1: ] :: [pool-1-thread-2]START
[Tasks by team2 : ] :: [pool-1-thread-3]START
[Tasks by WorkerOne : ] :: [pool-1-thread-1] END

Answer 1

{}class的闩锁变量从未初始化。我怀疑您打算，但忘记了，像在WorkerOne类中那样进行初始化

当在latch字段上调用countDown()时，在发布代码时执行该代码会使Team可运行程序抛出NullPointerException。主线程在其CountDownLatch上永远等待，因为它永远不会倒计时到0