系统休眠Sleep

每个对象都有一把锁，sleep不会释放锁

package Sleep;

import java.text.SimpleDateFormat;
import java.util.Date;

public class TestSleep {


    public static void main(String[] args) throws InterruptedException {
        //模拟倒计时
//        tenDown();

        //打印当前系统时间
        Date date = new Date(System.currentTimeMillis());
        while(true){
            Thread.sleep(1000);
            System.out.println(new SimpleDateFormat("HH:mm:ss").format(date));
            date = new Date(System.currentTimeMillis());
        }
    }

    public static void tenDown() throws InterruptedException {
        int num = 10;
        while (true){
            Thread.sleep(1000);
            System.out.println(num--);
            if (num <= 0)
                break;
        }
    }
}