Mutual Exclusion

//Mutual Exclusion
public class ThreadDemo extends Thread {

    int threadNo;

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

    public void run() {
        System.out.println("Thread " + threadNo + " entered the critical section.");
        System.out.println("Thread " + threadNo + " out of the critical section.");
    }

    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();
        t1.join();
        t2.join();
        t3.join();
    }
}