hibernate: optimistic concurrency control

I am trying to learn optimistic concurrency control.

The following program

1. opens a session, creates a row in table : id=1 name = "raj", commits and closes the session
2. start a thread, that sleeps initially for 3 sec. Then opens session2, updates the person having id =1 with name = "raj10". Then session2 is closed.
3. In session3, i modify the same db row (with id=1). But the thing is that, this row is loaded before the thread in step 2 loads the same db row. And in session3 the loaded db row is updated (now this is stale because thread in step2 already modified it). So i catch the staleObjectStateException. Inside the catch block i load it again, update and then save it.

i get the following exception: Exception in thread "main" org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.raj.hibernate.optimistic.OptPerson#1]

Please tell me

1. what i should have in my catch block to successfully update with new value.

2. would the session.merge help me here.

   final SessionFactory factory = new Configuration().configure()
           .buildSessionFactory();
   Session session = factory.openSession();
   session.beginTransaction();
   OptPerson optP1 = new OptPerson();
   optP1.setName("raj");
   session.save(optP1);
   session.getTransaction().commit();
   session.close();
   System.out.println("done saving, closed session");
   
   new Thread() {
       public void run() {
           try {
               Thread.sleep(3000);
           } catch (InterruptedException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
           Session session2 = factory.openSession();
           session2.beginTransaction();
           OptPerson p1 = (OptPerson) session2.get(OptPerson.class, 1);
           p1.setName("raj10");
           session2.save(p1);
           session2.getTransaction().commit();
           session2.close();
           System.out.println("modified person in session2");
       }
   }.start();
   
   Session session3 = factory.openSession();
   session3.beginTransaction();
   OptPerson p1 = (OptPerson) session3.get(OptPerson.class, 1);
   System.out.println("read person in session3");
   Thread.sleep(8000);
   try {
       p1.setName("man");
       session3.save(p1);
       session3.getTransaction().commit();
   } catch (StaleObjectStateException ex) {
       System.out.println("inside catch block");
       OptPerson p3 = (OptPerson) session3.get(OptPerson.class, 1);
       p3.setName("man");
       session3.saveOrUpdate(p3);
       //OptPerson p4 = (OptPerson) session3.merge(p1);
       session3.getTransaction().commit();
   } finally {
       session3.close();
   }