Instability recovering updated objects list

Question

I am facing problems with Hibernate that seems to be related to the cache object.

I have an entity, let’s call it A, with an attribute mapped list with @OneToMany (cascade = CascadeType.ALL, mappedBy = "atributo"). The objects in the list are class B entities and have a bidirectional relationship with A. So B has an attribute mapped with @ManyToOne (cascade = CascadeType.MERGE). I receive object A from the database and add a new object B in list A using the call and Session.update(A).

The problem arises when I list all objects of type A, using the call session.createCriteria(A.class).list();, access exactly to an A object that I updated and object B NAY is on the list. When opening Postgresql, both objects are updated and correctly saved, but sometimes in the query performed in the Criteria the data is not the same (sometimes they are correct and sometimes they are not).

I tried to use Session.refresh (A) after update A, but the problem still persists.

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About the comment of Caffé, I believe that this is what is happening, but I still can not find a solution to the problem. Below follows the implementation of save and update methods of Genericdao:

** Note that our Genericdao class is broken down using Threadlocal.

private static final ThreadLocal threadSession = new ThreadLocal();
private static final ThreadLocal threadTransaction = new ThreadLocal();

public GenericDao(final Class<T> objectClass) {
    this.objectClass = objectClass;
}

public Class<T> getObjectClass() {
    return this.objectClass;
}

public T save(final T object) throws HibernateException {
    try {
        final Session s = this.getSessionHibernate();
        s.beginTransaction();
        s.save(object);
        s.getTransaction().commit();
        s.flush();

        return object;
    } catch (final HibernateException ex) {
        GenericDao.logger.error(ex);

        Session s = this.getSessionHibernate();
        s.getTransaction().rollback();
        s.clear();

        throw new HibernateException(ex);
    }
}

public void update(final T object) throws HibernateException {
    try {
        final Session s = this.getSessionHibernate();
        s.update(object);           

    } catch (final HibernateException ex) {
        GenericDao.logger.error(ex);

        Session s = this.getSessionHibernate();
        s.getTransaction().rollback();
        s.clear();

        throw new HibernateException(ex);
    }
}

/**
 * Get session opened of the Hibernate
 * 
 * @return {@link Session}
 */
public Session getSessionHibernate() {
    Session s = (Session) GenericDao.threadSession.get();
    // Open a new Session, if this thread has none yet

    if (s == null) {
        s = this.getHibernateTemplate().getSessionFactory().openSession();
        GenericDao.threadSession.set(s);
    }
    return s;
}