Thread join on itself

I am in doubt, what happens when a thread joins itself. i.e thread calls the join method on its own. I am not getting any error.

Sample :

public class JoinItself extends Thread {

    public void run() {
        System.out.println("Inside the run method ");
        System.out.println(Thread.currentThread().isAlive());
        for(int i=0;i<5;i++) {
            try {
                System.out.println("Joining itself ...");
                Thread.currentThread().join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
    public static void main(String[] args) {

        JoinItself j = new JoinItself();

        System.out.println(j.isAlive());
        j.start();
        System.out.println(j.isAlive());
        System.out.println("Thread started ...");

    }

}

But Why? Should I get any error?