notify()唤醒线程，不会立即释放锁对象，需要等到当前同步代码块都执行完后才能释放锁对象 

public class Test3 {public static void main(String[] args) {List<String> list = new ArrayList<>();Thread thread1 = new Thread(new Runnable() {@Overridepublic void run() {synchronized (list) {if (list.size() != 5) {System.out.println("线程1开始等待" + System.currentTimeMillis());try {list.wait();} catch (InterruptedException e) {e.printStackTrace();}System.out.println("线程1被唤醒：" + System.currentTimeMillis());}}}}) {};Thread thread2 = new Thread(new Runnable() {@Overridepublic void run() {synchronized (list) {for (int i = 0; i < 10; i++) {list.add("data" + i);System.out.println("线程2添加第" + i + "个数据");if (list.size() == 5) {list.notify();System.out.println("线程2已经发现唤醒通知");}try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}}}}}) {};thread1.start();try {Thread.sleep(500);} catch (InterruptedException e) {e.printStackTrace();}thread2.start();}
}