为什么cyclicbarrier.await（int timeout,TimeUnit unit）没有在这里抛出TimeOutException？

Question

public class MyCyclicBarrier extends Thread{
    private CyclicBarrier cyclicBarrier;

    public MyCyclicBarrier(CyclicBarrier cyclicBarrier) {
        this.cyclicBarrier = cyclicBarrier;
    }

    @Override
    public void run() {
        System.out.println("Thread start."+Thread.currentThread().getName());
        try {
            TimeUnit.SECONDS.sleep(2);  //biz code
            System.out.println("Thread "+Thread.currentThread().getName()+" is waiting for the other Threads."+
                    "\n\t\t\t\tIt's parties is "+cyclicBarrier.getParties()+
                    "\n\t\t\t\tWaiting for "+cyclicBarrier.getNumberWaiting()+" Threads");
            cyclicBarrier.await(3,TimeUnit.SECONDS);
        } catch (InterruptedException | BrokenBarrierException | TimeoutException e) {
            e.printStackTrace();
        }
        System.out.println("Thread end."+Thread.currentThread().getName());
    }
}

public class TestCyclicbarrier_1 {
    public static void main(String[] args) {
        int length = 5;
        long start = System.currentTimeMillis();
        CyclicBarrier cyclicBarrierWithRunnable = new CyclicBarrier(length,()->{
            System.out.println("the final reach Thread is "+Thread.currentThread().getName());
            long end = System.currentTimeMillis();
            System.out.println("cost totally :"+(end-start)/1000+"s");
        });
        for (int i=0;i<length;i++){
            if (i!=4){
                new MyCyclicBarrier(cyclicBarrierWithRunnable).start();
            }else {
                try {
                    TimeUnit.SECONDS.sleep(2);
                    new MyCyclicBarrier(cyclicBarrierWithRunnable).start();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Thread start.Thread-1
Thread start.Thread-0
Thread start.Thread-2
Thread start.Thread-3
Thread Thread-0 is waiting for the other Threads.
                It's parties is 5
                Waiting for 0 Threads
Thread Thread-3 is waiting for the other Threads.
                It's parties is 5
                Waiting for 0 Threads
Thread start.Thread-4
Thread Thread-1 is waiting for the other Threads.
                It's parties is 5
                Waiting for 0 Threads
Thread Thread-2 is waiting for the other Threads.
                It's parties is 5
                Waiting for 1 Threads
Thread Thread-4 is waiting for the other Threads.
                It's parties is 5
                Waiting for 4 Threads
the final reach Thread is Thread-4
cost totally :4s
Thread end.Thread-4
Thread end.Thread-0
Thread end.Thread-3
Thread end.Thread-2
Thread end.Thread-1

我在网上找了很久。但没有类似的答案。请帮忙或试着给出一些想法。我刚刚开始学习CyclicBarrier，我想知道我是否误解了CyclicBarrier.Await（int timeout,TimeUnit unit）。线程0到3已经到达了花费2秒的障碍点。同时，最后一个线程在等待2秒后启动。1秒后，0到3个线程到达指定的超时，其中第4个线程仍然执行自己的代码。问题是：为什么CyclicBarrier.Await（int timeout,TimeUnit unit）没有在这里抛出TimeOutException？

Answer 1

线程0到3已经到达花费2秒的障碍点。

这是正确的。

在同一时间内，最终线程在等待2s后启动。

try {
    TimeUnit.SECONDS.sleep(4);
    new MyCyclicBarrier(cyclicBarrierWithRunnable).start();
} catch (InterruptedException e) {
     e.printStackTrace();
}