线程死锁问题

package com.day03;

/**
 * @author anyan
 * @date 2021/5/9-16:21
 */
/*
让线程进入死锁的方法
在开发中慎重使用synchronized嵌套，否则会出现死锁问题，程序不会报错，因此调试时很难发现
 */
public class DeadLock {
    public static void main(String[] args) {
        Object object1=new Object();
        Object object2=new Object();
        ThreadOne t1=new ThreadOne(object1,object2);
        ThreadTwo t2=new ThreadTwo(object1,object2);
        t1.start();
      /*// 如果在两个线程中间加一个延迟，可以解决极大可能存在的死锁问题，或者减少死锁的时间
        try {
            Thread.sleep(1000*5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }*/
        t2.start();
    }
}
class ThreadOne extends Thread {
    Object obj1;
    Object obj2;
    public ThreadOne(Object obj1,Object obj2){
        this.obj1=obj1;
        this.obj2=obj2;
    }
    public void run(){
        synchronized(obj1) {//先锁住obj1
            System.out.println(1.1);
            try {
                Thread.sleep(1000);//增加睡眠，一定会发生死锁
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (obj2){//后锁住obj2,指导Obj2被锁住，该方法才会被结束，否则一直执行
                System.out.println(1.2);
            }
        }
    }
}
class ThreadTwo extends Thread{
    Object obj1;
    Object obj2;
    public ThreadTwo(Object obj1,Object obj2){
        this.obj1=obj1;
        this.obj2=obj2;
    }
    public void run(){
        synchronized(obj2){
            System.out.println(2.1);
            synchronized(obj1){
                System.out.println(2.2);
            }
        }
    }
}