关于多线程的死锁问题，我想写一个死锁的程序，我什么我的两个程序，一个可以锁成功，另一个却不会

Question

第一份代码，可以锁成功

public class Main{

public static void main(String[] args){
    LockThread lock1 = new LockThread(true);
    LockThread lock2 = new LockThread(false);
    
    Thread thread1 = new Thread(lock1);
    Thread thread2 = new Thread(lock2);
    
    thread1.start();
    thread2.start();
}

}

class LockThread implements Runnable{

private boolean flag;

public LockThread(boolean flag){
    this.flag = flag;
}

public void run(){
    if (flag){
        synchronized(MyLock.lock1){
            System.out.println("锁住Lock1");
            synchronized(MyLock.lock2){
                System.out.println("锁住Lock2");
            }
        }
    }else{
        synchronized(MyLock.lock2){
            System.out.println("锁住Lock2");
            synchronized(MyLock.lock1){
                System.out.println("锁住Lock1");
            }
        }
    }
}

}

class MyLock{

public static final Object lock1 = new Object();
public static final Object lock2 = new Object();

}

第二份代码，锁不成功
public class Money {

public void say(){
    System.out.println("你给我钱，我给你笔记本电脑!");
}

}

public class Notebook {

public void say(){
    System.out.println("你给我电脑，我给你钱");
}

}

import java.util.concurrent.locks.Lock;

public class LockThread implements Runnable{

private boolean flag;
private Notebook hp;
private Money rmb;

public LockThread(Notebook hp, Money rmb, Boolean flag){
    this.hp = hp;
    this.flag = flag;
    this.rmb = rmb;
}

public void setFlag(boolean flag) {
    this.flag = flag;
}

public Notebook getHp() {
    return hp;
}

public void setHp(Notebook hp) {
    this.hp = hp;
}

public void setRmb(Money rmb) {
    this.rmb = rmb;
}

public Money getRmb() {
    return rmb;
}

public boolean isFlag() {
    return flag;
}

@Override
public void run() {
    if (flag){
        synchronized(hp){
            hp.say();
            synchronized (rmb){
                rmb.say();
            }
        }
    }else {
        synchronized (rmb){
            rmb.say();
            synchronized (hp){
                hp.say();
            }
        }
    }
}

}

public class Main {

public static void main(String[] args){
    Money rmb = new Money();
    Notebook hp = new Notebook();

    LockThread lock1 = new LockThread(hp, rmb, true);
    LockThread lock2 = new LockThread(hp, rmb, false);

    Thread thread1 = new Thread(lock1);
    Thread thread2 = new Thread(lock2);

    thread1.start();
    thread2.start();
}

}

Answer 1

按道理来说，你第二份代码是可能出现死锁的
你没出现死锁可能是因为thread1比thread2早申请到了rmb，因为thread1.start()比thread2.start()早开始