I am trying to implementing deadlock condition but somehow I am not able to get it working. Both the threads Thread1 and Thread2 are entering in the run function but only one of them enters in Sub/Sum depending on who entered run first. Example : if Thread2 entered run first the it will call sub() and Thread1 never calls sum(). I have also added sleep time so that Thread2 sleeps before calling sum() and Thread1 gets enough time to enter Sum() but Thread1 never enters.

    public class ExploringThreads {
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            threadexample a1 = new threadexample();
            Thread t1 = new Thread(a1, "Thread1");
            Thread t2 = new Thread(a1,"Thread2");
            t1.start();
            t2.start();
        }
    }
    class threadexample implements Runnable{
        public int a = 10;
        public void run(){
            if(Thread.currentThread().getName().equals("Thread1"))
                sum();
            else if(Thread.currentThread().getName().equals("Thread2"))
                sub();
        }

        public synchronized void sum()
        {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"In Sum");
            sub();
        }

        public synchronized void sub()
        {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"In Sub");
            sum();
        }
    }