wait 执行后自动释放锁，notify执行不释放锁

wait 执行后自动释放锁，notify执行不释放锁

wait 执行后自动释放锁

1. 当wait在锁里面时，执行到wait之后 锁会被释放
2. 当notify在锁里面时，执行到notify 时wait被唤醒，但是线程不释放锁

测试代码如下：

package com.chapter03;class Service02 {public void testMethod(Object lock) {try {synchronized (lock) {System.out.println("begin wait");lock.wait();System.out.println("end wait");}} catch (InterruptedException e) {e.printStackTrace();}}}class ThreadA extends Thread {private Object lock;public ThreadA(Object lock) {this.lock = lock;}@Overridepublic void run() {Service02 service02 = new Service02();stMethod(lock);}
}class ThreadB extends Thread {private Object lock;public ThreadB(Object lock) {this.lock = lock;}@Overridepublic void run() {Service02 service02 = new Service02();stMethod(lock);}
}public class StudyThreads02释放锁与不释放锁 {public static void main(String[] args) {Object lock = new Object();ThreadA threadA = new ThreadA(lock);ThreadB threadB = new ThreadB(lock);threadA.start();threadB.start();}
}

执行结果： 执行到wait之后 锁被释放，线程B拿到锁开始执行直到wait 继续等待。

notify执行不释放锁

1. 执行到notify之后唤醒相应线程，但是本线程不会释放锁，直到执行完毕才会释放锁

wait状态时候执行 interrupt

1. 当线程处于wait状态时候，执行interrupt方法程序会出现InterruptedException异常

释放锁的几个条件

1. 同步代码块执行完毕，释放锁
2. 执行同步代码块遇到异常导致线程终止，释放锁
3. 执行同步代码块