hibernate session.save() does not reflect in database

Question

According to my understanding in hibernate (please confirm)

1- You have to session.close() if you get it by getSessionFactory().openSession()

Answer 1

I was also trying to understand the point: save() can perform Insert operation outside transaction boundary so I did something like this

SessionFactory factory = new Configuration().configure()
                    .buildSessionFactory();
            Session session = factory.openSession();

            session.save(user);

            session.close();

But data not inserted in database.So I again tried this and now it worked for me and data inserted sucessfully:

in configuration file:

  true

and in java code:

    SessionFactory factory = new Configuration().configure()
            .buildSessionFactory();
    Session session = factory.openSession();

    session.save(user);

    session.flush();
    session.close();