Main19.java

public class Main19 {
    public static void main(String[] args) throws InterruptedException {

        Object obj = new Object();
        Runnable r1 = () -> {
            try {
                synchronized (obj) {
                    obj.wait();
                }
            } catch (InterruptedException ex) {
                System.out.println("interrupted");
            }
        };

        Runnable r2 = () -> {
            synchronized (obj) {
                obj.notifyAll();
                try {
                    Thread.sleep(10000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }

        };

        Thread t0 = new Thread(r1);
        t0.start();
        Thread t1 = new Thread(r1);
        t1.start();
        Thread t2 = new Thread(r1);
        t2.start();
        Thread t3 = new Thread(r1);
        t3.start();
        Thread t4 = new Thread(r2);
        t4.start();
    }
}