protected void entityIsTransient(MergeEvent event, Map copyCache) {
        super.entityIsTransient(event, copyCache);
        SessionImplementor session = event.getSession();
        EntityPersister persister = session.getEntityPersister(event.getEntityName(), event.getEntity());
        // Extract id from merged copy (which is currently registered with Session).
        Serializable id = persister.getIdentifier(event.getResult(), session.getEntityMode());
        // Set id on original object (which remains detached).
        persister.setIdentifier(event.getOriginal(), id, session.getEntityMode());
        // the variable id is not holding the ID as the right_id column at DB, it holds the object's default value
    }

<?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="model.Right" table="system_right">
      <id name="id" column="right_id">
         <generator class="native"/>
      </id>
      <property unique="true" name="name" length="50"/>
      <property name="type"/>
      <property name="description"/>
   </class>

</hibernate-mapping>

    tx = hsession.beginTransaction();
    Right right = new Right();
    ...
       set values
    ...
    session.merge(right);
    // the id still 0
    // i also try session.refresh(right); after marge
    // and query it by its onw example