import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import java.sql.Timestamp;

@XmlRootElement
public class Payment
{
    public Payment(int id, int clientId, String paymenttype, int paymentvalue, int account, Timestamp timestamp) {
        this.id = id;
        this.clientId = clientId;
        this.paymenttype = paymenttype;
        this.paymentvalue = paymentvalue;
        this.account = account;
        this.timestamp = timestamp;
    }

    public Payment() {

    }


    int id = 0;

    int clientId = 0;

    String paymenttype = "";

    int paymentvalue = -1;

    int account = -1;

    Timestamp timestamp;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @XmlAttribute
    public int getClientId() {
        return clientId;
    }

    public void setClientId(int clientId) {
        this.clientId = clientId;
    }

    @XmlElement
    public String getPaymenttype() {
        return paymenttype;
    }

    public void setPaymenttype(String paymenttype) {
        this.paymenttype = paymenttype;
    }

    @XmlElement
    public int getPaymentvalue() {
        return paymentvalue;
    }

    public void setPaymentvalue(int paymentvalue) {
        this.paymentvalue = paymentvalue;
    }

    @XmlElement
    public int getAccount() {
        return account;
    }

    public void setAccount(int account) {
        this.account = account;
    }

    public Timestamp getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(Timestamp timestamp) {
        this.timestamp = timestamp;
    }
}

Также есть Payment.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="Payment" table="BufferPaymentTable">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="increment" />
        </id>

        <property name="clientid" type="java.lang.Integer">
        <column name="clientid" length="10" not-null="true" unique="false" />
        </property>

        <property name="paymenttype" type="string">
            <column name="paymenttype" length="20" not-null="true" unique="false" />
        </property>

        <property name="account" type="java.lang.Integer">
        <column name="account" length="10" not-null="true" unique="false" />
        </property>

        <property name="paymentvalue" type="java.lang.Integer">
        <column name="paymentvalue" length="10" not-null="true" unique="false" />
    </property>

        <property name="timestamp" type="java.sql.Timestamp">
            <column name="currenttime"  not-null="true" unique="false" />
        </property>

    </class>
</hibernate-mapping>

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

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;
    }
}

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

            session.beginTransaction();
            ........................
            session.getTransaction().commit();

session.close();

    public void init(javax.servlet.ServletConfig config)
            throws javax.servlet.ServletException
    {
          ......
          session = HibernateUtil.createSessionFactory().openSession();

    }
.......
    public void destroy() {
        .....
        session.close();
    }

            session.beginTransaction();

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

                        query =  session.createQuery(
                                "from BufferPaymentTable BFT where BFT.paymenttype = :paymenttype  and BFT.currenttime < :currenttime");
                        query.setParameter("paymenttype", strtype);
                        query.setParameter("currenttime", timestamp);

            Session session = HibernateUtil.createSessionFactory().openSession();
            session.beginTransaction();

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

        while (ServerConfig.getServerConfig().isServerworking())
        {
            try
            {
                Thread.sleep(5000);


                Logger.getLogger().write("before loadallPaymentsFromBufferAndSaveAsProcessing");

                Session session = HibernateUtil.createSessionFactory().openSession();

                session.beginTransaction();

                Query query = session.createSQLQuery("select now();");
                List <Timestamp> timestampList =  query.list();
                Timestamp timestamp = timestampList.get(0);

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

                boolean newData = false;

                session = HibernateUtil.createSessionFactory().openSession();

                session.beginTransaction();

                NodeList nList = ServerConfig.getServerConfig().getnList();

                /**
                 * загружаем из временной буфер-таблицы все полученные от клиентов даннык.
                 */

                List <ArrayList<Payment>> listsOfAllPayments = new  ArrayList <ArrayList<Payment>>();

                for (int i = 0; i < nList.getLength(); i++) {

                    Node nNode = nList.item(i);
                    Element eElement = (Element) nNode;
                    List<Payment> listsOfPayments = null;

                    if (nNode.getNodeType() == Node.ELEMENT_NODE) {

                        String strtype = eElement.getElementsByTagName("paymenttype").item(0).getTextContent();

                        query =  session.createQuery(
                                "from Payment  where paymenttype = :paymenttype and currenttime < :currenttime");
                        query.setParameter("paymenttype", strtype);
                        query.setParameter("currenttime", timestamp);

                        listsOfPayments = (List<Payment>)query.list();
                    }

                    if (listsOfPayments.size() > 0)
                        newData = true;

                    // Сохраняем эти данные в список списков (упорядочено по типу платежа)
                    listsOfAllPayments.add((ArrayList)listsOfPayments);
                }

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


                List<ArrayList<OperationPaymentData>> listsOfAllProcessingPayments = new ArrayList<ArrayList<OperationPaymentData>>();

                if (newData) {
                    /**
                     * Сохраняем все платежи в таблицу операций со статусом 'processing'
                     */
                    session = HibernateUtil.createSessionFactory().openSession();
                    session.beginTransaction();

                    for (int i = 0; i < listsOfAllPayments.size(); i++) {

                        List<Payment> listsOfPayments = listsOfAllPayments.get(i);
                        ArrayList<OperationPaymentData> listsOfProcessingPaymentsOfThisType = new ArrayList<OperationPaymentData>();

                        OperationPaymentData operationPaymentData = null;

                        for (int j = 0; j < listsOfPayments.size(); j++) {
                            Payment payment = listsOfPayments.get(j);
                            operationPaymentData = new OperationPaymentData(payment.getId(), payment.getClientId(), payment.getPaymenttype(),
                                    payment.getAccount(), payment.getPaymentvalue(), payment.getTimestamp());

                            listsOfProcessingPaymentsOfThisType.add(operationPaymentData);

                            session.save(operationPaymentData);
                        }

                        listsOfAllProcessingPayments.add(listsOfProcessingPaymentsOfThisType);

                        Logger.getLogger().write("loadallPaymentsFromBufferAndSaveAsProcessing3");
                    }

                    session.getTransaction().commit();
                    session.close();
                }
                /**
                 * удаляем из буфер-таблицы извлеченные оттуда записи
                 */

                session = HibernateUtil.createSessionFactory().openSession();
                session.beginTransaction();
                query =  session.createQuery(
                        "delete  from Payment  where  currenttime < :currenttime");
                query.setParameter("currenttime", timestamp);
                query.executeUpdate();

                session.getTransaction().commit();

                session.close();

                Logger.getLogger().write("after loadallPaymentsFromBufferAndSaveAsProcessing");

                for (ArrayList<OperationPaymentData> listsOfProcessingPaymentsOfThisType : listsOfAllProcessingPayments) {

                    if (listsOfProcessingPaymentsOfThisType.size() > 0) {
                        String strtype = listsOfProcessingPaymentsOfThisType.get(0).getPaymenttype();


                        PayData paydata = new PayData();
                        Logger.getLogger().write("Sending to operator, paymenttype = " + listsOfProcessingPaymentsOfThisType.get(0).getPaymenttype());
                        paydata.proceedPayments(listsOfProcessingPaymentsOfThisType, ServerConfig.getServerConfig().getURLByType(strtype));
                    }

                }
            } catch (Exception e) {
                Logger.getLogger().write("PaymentRouter, ex " + e.toString());
            }

        }

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;
    }

GenerationType.IDENTITY