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 ThreadCounter implements Runnable {
    private static int count = 0;

    private Thread t;

    public ThreadCounter(String tName){
        t= new Thread(this, tName);
        t.start();
    }

    @Override
    public void run() {
        for(int i=1; i<=5; i++){
            synchronized (CommonUtil.mLock) {
                incrementCount(t.getName());
                CommonUtil.mLock.notify();
                try {
                    CommonUtil.mLock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void incrementCount(String tName){
        System.out.println(tName+": "+(++ThreadCounter.count));
    }

    public static void main(String[] args) throws InterruptedException {
        new ThreadCounter("Thread1");
        Thread.sleep(500);
        new ThreadCounter("Thread2");
    }

}

class CommonUtil{
    public static Object mLock = new Object();
}