public static class Thread2 extends Thread {
        public void run() {
            try {
                while(!this.isInterrupted()){
                    Thread.sleep(1000);
                }
            } catch (InterruptedException e){
                System.out.println("InterruptedException");
            }
            //System.out.println("InterruptedException");
        }
    }
为什么 线程4 这样不行 , 需要去掉“//”才能通过