Mutual Exclusion!

//Mutual Exclusion

import java.util.concurrent.locks.*;

public class ThreadDemo extends Thread {

    int threadNo;
    Lock lock = new ReentrantLock();

    ThreadDemo(int x) {
        this.threadNo = x;
    }

    @Override
    public void run() {
        try {
            lock.lock();
            System.out.println("Thread " + threadNo + " entered the critical section.");
            System.out.println("Thread " + threadNo + " out of the critical section.");
        } finally {
            lock.unlock();
        }
    }

    public static void main(String argsp[]) throws InterruptedException {
        ThreadDemo t1 = new ThreadDemo(1);
        ThreadDemo t2 = new ThreadDemo(2);
        ThreadDemo t3 = new ThreadDemo(3);
        t1.start();
        t2.start();
        t3.start();

    }
}