Writing a program with 2 threads which prints alternatively

Question

I got asked this question recently in an interview.

Write a program with two threads (A and B), where A prints 1 , B prints 2 and so on until 50 is r

Answer 1

public class PingPong extends Thread {
static StringBuilder object = new StringBuilder("");

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

    Thread t1 = new PingPong();
    Thread t2 = new PingPong();

    t1.setName("\nping");
    t2.setName(" pong");

    t1.start();
    t2.start();
}

@Override
public void run() {
    working();
}

void working() {
    while (true) {
        synchronized (object) {
            try {
                System.out.print(Thread.currentThread().getName());
                object.notify();
                object.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

}