public class Main {

    public static void main(String[] args) {
        Main main = new Main();
        main.test();
    }

    private void test() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(5000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println("唤醒等待线程");
                
                synchronized (Main.class) {
                    Main.class.notifyAll();
                }
            }
        }).start();

        synchronized (Main.class) {
            try {
                System.out.println("等待...");
                Main.class.wait();

                System.out.println("等待结束");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

 

输出：

等待...
唤醒等待线程
等待结束