Problems with Session.save()

Question

I'm new to hibernate and as I researched, I have found out that the HQL insert query gets data from other tables. According to what I've read, I can make use of session.save for the insert functionality. In my DAO I have this addToCart() method

@Override
public void addToCart(ShoppingCart cart) {

    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction transaction = session.beginTransaction();

    session.save(cart);
    transaction.commit();
    session.close();

}

The code above doesn't work. Maybe I am missing something because I'm still new to hibernate.