Session session = HibernateUtil.createSessionFactory().openSession();
[SRC java]            session.beginTransaction();

            session.save(payment);
            session.getTransaction().commit();
            session.close();

public class HibernateUtil {
    private static SessionFactory sessionFactory;
    private static ServiceRegistry serviceRegistry;

    public static SessionFactory createSessionFactory() {
        Configuration configuration = new Configuration();
        configuration.configure();
        serviceRegistry = new StandardServiceRegistryBuilder().applySettings(
                configuration.getProperties()).build();
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        return sessionFactory;
    }
}

public class HibernateUtil {
    private static SessionFactory sessionFactory = null;
    private static ServiceRegistry serviceRegistry;

    public static SessionFactory getSessionFactory() {
        if (sessionFactory == null)
            createSessionFactory();
        return sessionFactory;
    }

    private static void createSessionFactory() {
        Configuration configuration = new Configuration();
        configuration.configure();
        serviceRegistry = new StandardServiceRegistryBuilder().applySettings(
                configuration.getProperties()).build();
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
    }
}

            session.beginTransaction();

            session.save(payment);
            session.getTransaction().commit();

        session.save(myclass);//сохранили, наш id сгенерировался и сразу заполнился
        myclass = (MyСlass) session.get(MyСlass.class, myclass.getId());

        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="increment" />
        </id>

public static int getNextId() {

        Session session = null;
        int id = 1;

        try {

            session = getSessionFactory().openSession();
            Query query = session.createSQLQuery("select max(paymentid) from OperationPaymentTable");
            List<Integer> list = query.list();
            id = list.get(0) + 1;

            Logger.getLogger().write("ID = " +id);

        } catch (Exception ex) {
            Logger.getLogger().write("HibernateUtil.getNextId, ex = " + ex.toString());
        } finally {
            session.close();
        }
        
        return id;
    }