I've started to work with JBOSS EJB 3.0 Embeddable. When I tried to get elements form lazy initialization colection, a org.hibernate.LazyInitializationException occured. Why that exception doesn't have a JSR-220 counterpart?? What can I do against this situation? I've read many comments on forums and google but all related with hibernate core, not with EJB3.0. I don't want to break the portability of my code.

Any helps and hints are very welcome.

Thx in advance. Regards JTONIC.

Well there is nothing with portability!
You've got this exception on JBoss, and some Oracle exception on Oracle AS, and some weblogic exception on Weblogic ....

because hibernate load the lists lazily by default, when you are trying to get the list, Hibernate will go to select from database at that time, and I think there is no session at that moment.

you can set the FetchMode of the list to FetchMode.EAGER or FetchMode.JOIN and disable lazy loading of hibernate for that list.

@Basic(fecth=FetchMode.JOIN)

Hope this help you

please send your full stack trace exception and also your class definitions for this situation.



Regards
Mohammad Norouzi

JBoss Seam work around the problem in an elegant way

Hi Emmanuel,

What do you mean with

please ?

I' working on Seam but I have defined my DAO classes as stateless beana which are called from the stateful session bean.

I'm always getting the org.hibernate.LazyInitializationException if i don't fetch the content in my HQL queries ( I haven't modify the annotations because I always hope I will be able to do the lazy fecthing working )

Any idea how to keep the session open when the entity manager is in a stateless bean ?

Thanks in advance for any feedback.

Christophe

The solution is really simple: If you want to keep the state of the persistence context across requests and/or during RENDER_RESPONSE, don't close the persistence context too early. In other words, if you want to keep state, why are you using a stateless component?

In Seam you'd use a Seam managed persistence context (@In EntityManager) in a stateful conversational component. You will never see a LIE again if you don't try to move entity objects between conversational components (which is an anti-pattern).

This should go to the Seam forum, so please bring this up there if you want to know how Seam works.

In case this isn't clear: The @In EntityManager goes into your stateful component. As long as you call your stateless DAO component within a method that has a transaction, the transaction _and_ the persistence context will be propagated into the stateless component during the call.

Thanks a lot Christian, for both the clarity and the rapidity of your answer !