Java多线程锁

AQS

互斥锁，悲观锁

public class Demo1 {// 从0累加到1000 悲观锁static Integer num = 0;public static void main(String[] args) {for (int i = 0; i < 3; i++) {Thread t = new Thread(() -> {while (num < 1000) {synchronized (num.getClass()) {if (num < 1000) {System.out.println("thread name:" + Thread.currentThread().getName() + ":" + (++num));}}}});t.start();}}
}

乐观锁

读操作不需要上锁

CAS

比较后交换，必须是原子性