/**
    * Instantiate the entity class. Return <tt>null</tt> to indicate that Hibernate should use
    * the default constructor of the class. The identifier property of the returned instance
    * should be initialized with the given identifier.
    *
    * @param entityName the name of the entity
    * @param entityMode The type of entity instance to be returned.
    * @param id the identifier of the new instance
    * @return an instance of the class, or <tt>null</tt> to choose default behaviour
    */
   public Object instantiate(String entityName, EntityMode entityMode, Serializable id) throws CallbackException;