JAva volatileキーワードとinterrupt()を使用してスレッドを停止

public class Demo {
    private volatile static boolean shutdown;
    public static void main(String[] args) throws InterruptedException {

        Runnable runnable=()->{
            while (!shutdown){
                System.out.println("safe...");
            }
        };
        Thread t1 = new Thread(runnable, "t1");
        t1.start();
        System.out.println(t1.getName() +" ("+t1.getState()+") is started.");
        Thread.sleep(3000);
        shutdown=true;
        System.out.println(t1.getName() +" ("+t1.getState()+") is interrupted now.");


    }
}

public class Demo {
    private volatile static boolean shutdown;
    public static void main(String[] args) throws InterruptedException {
        Runnable interruptTask = new Runnable() {
            @Override
            public void run() {
                int i = 0;
                try {
                    //        ，             ，                 
                    while (!Thread.currentThread().isInterrupted()) {
                        Thread.sleep(100); //   100ms
                        i++;
                        System.out.println(Thread.currentThread().getName() + " (" + Thread.currentThread().getState() + ") loop " + i);
                    }
                } catch (InterruptedException e) {
                    //            InterruptedException  。（  ，catch        。）
                    System.out.println(Thread.currentThread().getName() + " (" + Thread.currentThread().getState() + ") catch InterruptedException.");
                }
            }
        };
        Thread t1 = new Thread(interruptTask, "t1");
        System.out.println(t1.getName() +" ("+t1.getState()+") is new.");

        t1.start();                      //   “  t1”
        System.out.println(t1.getName() +" ("+t1.getState()+") is started.");

        //      300ms，      t1 “  ”  。
        Thread.sleep(3000);
        t1.interrupt();
        System.out.println(t1.getName() +" ("+t1.getState()+") is interrupted.");

        //      300ms，    t1   。
        Thread.sleep(300);
        System.out.println(t1.getName() +" ("+t1.getState()+") is interrupted now.");


    }
}