Unable to locate current JTA transaction error

[Yahya Elyasse]

Hi guys,
from a MDB onMessage(Message ) method i call code that use hibernate persistence api to retreive data from a database.
this call raises 'Unable to locate current JTA transaction' exception below. i'm including the code for hibernate persistencelayer.
can someone help me fix this problem?
thanks.

Exception:

org.hibernate.HibernateException: Unable to locate current JTA transaction
at org.hibernate.context.JTASessionContext.currentSession(JTASessionContext.java:61)
at org.hibernate.impl.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:544)
at com.sapienter.jbilling.server.util.db.AbstractDAS.getSession(AbstractDAS.java:100)
at com.sapienter.jbilling.server.util.db.AbstractDAS.find(AbstractDAS.java:120)
at com.sapienter.jbilling.server.order.OrderBL.set(OrderBL.java:147)
at com.sapienter.jbilling.server.order.OrderBL.<init>(OrderBL.java:112)
at com.sapienter.jbilling.server.provisioning.task.ProvisioningCommandsMDB.onMessage(ProvisioningCommandsMDB.java:83)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
more...    

hibernate logic code:

  private static final Logger LOG = Logger.getLogger(AbstractDAS.class);
    private static SessionFactory sessionFactory;
    private EntityManager em = null;
    private Class<T> persistentClass;
    //  use "jbilling-jta" for JTA or "jbilling-jdbc" for jdbc
    private static final EntityManagerFactory emf =
        Persistence.createEntityManagerFactory("jbilling-jta"); 
    // if querys will be run cached or not
    private boolean queriesCached = false;
 
    
    // Create the initial SessionFactory from the default configuration files
    static {
        try {
            LOG.debug("Initializing Hibernate");
 
            sessionFactory = ((HibernateEntityManagerFactory) emf).getSessionFactory();
 
            LOG.debug("Hibernate initialized");
        } catch (Throwable ex) {
            // We have to catch Throwable, otherwise we will miss
            // NoClassDefFoundError and other subclasses of Error
            LOG.error("Building SessionFactory failed.", ex);
            throw new ExceptionInInitializerError(ex);
        }
    }
    
    public AbstractDAS() {
        this.persistentClass = (Class<T> :wink:  ((ParameterizedType) getClass()
                                .getGenericSuperclass()).getActualTypeArguments()[0];
    }
 
    
    /**
     * Merges the entity, creating or updating as necessary
     * @param newEntity
     * @return
     */
    public T save(T newEntity) {
        //T retValue = em.merge(newEntity);
        T retValue = (T) getSession().merge(newEntity);
        return retValue;
    }
    
    public void delete(T entity) {
        //em.remove(entity);
        getSession().delete(entity);
    }
 
    protected Session getSession() {
        Session mySession = null;
        if (em != null) {
            mySession = ((HibernateEntityManager) em).getSession();
        } else {
            mySession = sessionFactory.getCurrentSession();
        }
        return mySession;
    }
    
    public Class<T> getPersistentClass() {
        return persistentClass;
    }
 
    /**
     * This will load a proxy. If the row does not exist, it still returns an
     * object (not null) and  it will NOT throw an
     * exception (until the other fields are accessed).
     * Use this by default, if the row is missing, it is an error.
     * @param id
     * @return
     */
    @SuppressWarnings("unchecked")
    public T find(Serializable id) {
    if (id == null) return null;
        T entity = (T) getSession().load(getPersistentClass(), id);
 
        return entity;
    }
    
    /**
     * This will hit the DB. If the row does not exist, it will NOT throw an
     * exception but it WILL return NULL
     * @param id
     * @return
     */
    @SuppressWarnings("unchecked")
    public T findNow(Serializable id) {
    if (id == null) return null;
        T entity = (T) getSession().get(getPersistentClass(), id);
 
        return entity;
    }    
 
    @SuppressWarnings("unchecked")
    public List<T> findAll() {
        return findByCriteria();
    }
 
    @SuppressWarnings("unchecked")
    public List<T> findByExample(T exampleInstance, String... excludeProperty) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        Example example =  Example.create(exampleInstance);
        for (String exclude : excludeProperty) {
            example.excludeProperty(exclude);
        }
        crit.add(example);
        crit.setCacheable(queriesCached);
        return crit.list();
    }
 
    @SuppressWarnings("unchecked")
    public T findByExampleSingle(T exampleInstance, String... excludeProperty) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        Example example =  Example.create(exampleInstance);
        for (String exclude : excludeProperty) {
            example.excludeProperty(exclude);
        }
        crit.add(example);
        crit.setCacheable(queriesCached);
        return (T) crit.uniqueResult();
    }
    
    @SuppressWarnings("unchecked")
    public T makePersistent(T entity) {
        getSession().saveOrUpdate(entity);
        return entity;
    }
 
    public void makeTransient(T entity) {
        getSession().delete(entity);
    }
 
    public void flush() {
        getSession().flush();
    }
 
    public void clear() {
        getSession().clear();
    }
 
    /**
     * Use this inside subclasses as a convenience method.
     */
    @SuppressWarnings("unchecked")
    protected List<T> findByCriteria(Criterion... criterion) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        for (Criterion c : criterion) {
            crit.add(c);
        }
        crit.setCacheable(queriesCached);
        return crit.list();
   }
 
    @SuppressWarnings("unchecked")
    protected T findByCriteriaSingle(Criterion... criterion) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        for (Criterion c : criterion) {
            crit.add(c);
        }
        crit.setCacheable(queriesCached);
        return (T) crit.uniqueResult();
   }
 
    protected void useCache() {
        queriesCached = true;
    }
    
    /**
     * Makes this DTO now attached to the session and part of the persistent context.
     * This WILL trigger an update, which is usually fine since the reason to reattach
     * is to modify the object.
     * @param dto
     */
    public void reattach(T dto) {
    getSession().update(dto);
    }