synchronized中的死锁

案例:

package com.javaSe.DeadLock;
/*
死锁代码要会写。
    一般面试官会要求你会写。
    只有会写的，才会在以后的开发中注意这个事情。
    因为死锁很难调试。
*/
public class DeadfLock {
    public static void main(String[] args) {
        Object o1 = new Object();
        Object o2 = new Object();
        
        // t1和t2两个线程共享o1,o2
        Thread t1 = new MyThread1(o1,o2);
        Thread t2 = new MyThread2(o1,o2);
        
        t1.start();
        t2.start();
    }
}


class MyThread1 extends Thread{
    Object o1;
    Object o2;
    
    public MyThread1(Object o1,Object o2){
        this.o1 = o1;
        this.o2 = o2;
    }
    
    public void run(){
        synchronized(o1){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (o2){
            
            }
        }
    }
}


class MyThread2 extends Thread{
    Object o1;
    Object o2;
    
    public MyThread2(Object o1,Object o2){
        this.o1 = o1;
        this.o2 = o2;
    }
    
    public void run(){
        synchronized(o2){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (o1){
            
            }
        }
    }
}