the first code can be locked successfully
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("Lock1");
synchronized(MyLock.lock2){
System.out.println("Lock2");
}
}
}else{
synchronized(MyLock.lock2){
System.out.println("Lock2");
synchronized(MyLock.lock1){
System.out.println("Lock1");
}
}
}
}
}
class MyLock {
public static final Object lock1 = new Object();
public static final Object lock2 = new Object();
}
second code, lock is not successful
public class Money {
public void say(){
System.out.println("!");
}
}
public class Notebook {
public void say(){
System.out.println("");
}
}
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();
}
}