wait 释放锁

class ThreadB2 extends Thread {

    /**
     * 线程 BBB 持有对象锁 this，即当前对象 threadB2
     */
    @Override
    public void run() {
        synchronized (this) {
            System.out.println(Thread.currentThread().getName() + " beg "
                    + System.currentTimeMillis());
            System.out.println("B2 ing");
            System.out.println(Thread.currentThread().getName() + " end "
                    + System.currentTimeMillis());
        }
    }
}

class ThreadA2 extends Thread {

    private ThreadB2 threadB2;

    public ThreadA2(ThreadB2 threadB2) {
        this.threadB2 = threadB2;
    }

    /**
     * 线程 AAA 持有对象锁 threadB2
     */

    @Override
    public void run() {
        //B2 被锁住
        synchronized (threadB2) {
            System.out.println(Thread.currentThread().getName() + " beg "
                    + System.currentTimeMillis());
            try {
                System.out.println("wait之前：" + threadB2.isAlive());
                threadB2.wait();
                System.out.println("wait之后：" + threadB2.isAlive());
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
//            try {
//                Thread.sleep(2000);
//            } catch (InterruptedException e) {
//            }
            System.out.println(Thread.currentThread().getName() + " end "
                    + System.currentTimeMillis());
        }
    }
}

class Run2 {

    public static void main(String[] args) {
        ThreadB2 threadB2 = new ThreadB2();
        threadB2.setName("B2");
        ThreadA2 threadA2 = new ThreadA2(threadB2);
        threadA2.setName("A2");



        threadA2.start();
        threadB2.start();
    }

}