ClassCastException on EntityManager.getDelegate call

chawax · **Joined:** Mon Jan 10, 2005 7:14 am **Posts:** 32

Hi,

I have a ClassCastException on call to getDelegate method of EntityManager class. My code is as following :

Code:

protected javax.persistence.EntityManager emanager;

protected org.hibernate.ejb.HibernateEntityManager hibernateSession;

@javax.persistence.PersistenceContext(unitName = "t4Seam")    
public void setEntityManager(javax.persistence.EntityManager entityManager) {
    this.emanager = entityManager;
    this.hibernateSession = (org.hibernate.ejb.HibernateEntityManager) entityManager.getDelegate(); 
}

And the stack trace :

Code:

Caused by: java.lang.ClassCastException: org.hibernate.impl.SessionImpl
   at t4.core.user.internal.UserAccountDaoBase.setEntityManager(UserAccountDaoBase.java:41)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.injection.JndiMethodInjector.inject(JndiMethodInjector.java:94)
   at org.jboss.injection.JndiMethodInjector.inject(JndiMethodInjector.java:84)
   at org.jboss.injection.JndiMethodInjector.inject(JndiMethodInjector.java:58)
   at org.jboss.ejb3.AbstractPool.create(AbstractPool.java:111)
   at org.jboss.ejb3.InfinitePool.get(InfinitePool.java:49)
   at org.jboss.ejb3.ThreadlocalPool.create(ThreadlocalPool.java:50)
   at org.jboss.ejb3.ThreadlocalPool.get(ThreadlocalPool.java:90)
   at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:54)
   at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
   at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
   at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:110)
   at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
   at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
   at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
   at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
   at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
   at org.jboss.ejb3.stateless.StatelessContainer.localInvoke(StatelessContainer.java:240)
   at org.jboss.ejb3.stateless.StatelessContainer.localInvoke(StatelessContainer.java:210)
   at org.jboss.ejb3.stateless.StatelessLocalProxy.invoke(StatelessLocalProxy.java:84)
   at $Proxy306.findByUsername(Unknown Source)
   at t4.core.user.internal.UserInternalServiceBean.handleLoadUserAccount(UserInternalServiceBean.java:48)
   at t4.core.user.internal.UserInternalServiceBase.loadUserAccount(UserInternalServiceBase.java:97)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at 

What is strange is that this piece of code is OK on unit tests running with OpenEJB. The problem occurs when running on JBoss AS only.

I thought it could come from conflicts between Hibernate jars bundled in JBoss AS and the ones in my EAR (hibernate-3.2.0.GA, hibernate-annotations-3.2.0.GA and hibernate-entitymanager-3.2.0.GA), but removing them from lib JBoss directory changed nothing.

Anyone encoutered a similar problem ?

Olivier

chawax · **Joined:** Mon Jan 10, 2005 7:14 am **Posts:** 32

Sorry for multiposts, I had an error after submitting my post.

andydale · **Posted:** Tue Jul 15, 2008 5:27 am

Hi,

Try the following

Code:

session = (Session)((EntityManagerImpl)mEntityManager.getDelegate()).getDelegate();

cheers,

Andy

chawax · **Joined:** Mon Jan 10, 2005 7:14 am **Posts:** 32

Thanks for your help Andy.

Anyway it still doesn't work on JBoss AS. Still the same class cast exception when casting entityManager.getDelegate().

I debugged my piece of code, and entityManager is of org.jboss.ejb3.entity.TransactionScopedEntityManager type. So calling getHibernateSession() would work on it, but I guess this will not work with other application servers and this is an important point for my project. I will ask on JBoss forums to have help about this.

hardy.ferentschik · **Posted:** Tue Jul 15, 2008 6:22 am

Hi,

I think your cast is wrong. You should cast to org.hibernate.Session.
The implementation in AbstractEntityManagerImpl is:

Code:

   public Object getDelegate() {
      return getSession();
   }

--Hardy

P.S. I deleted the duplicated posts.

chawax · **Joined:** Mon Jan 10, 2005 7:14 am **Posts:** 32

Yes, you are right, it works on JBoss AS ... but it doesn't work on Open EJB !
Actually, with Open EJB, getDelegate method returns Hibernate entity manager. With JBoss AS, it returns Hibernate session ! Don't know which one does it the right way! Anyway, I find more logical to get entity manager rather than session. Anyone has an idea about this ?

Since I need my code to run on both application servers, I wrote it this way :

Code:

protected javax.persistence.EntityManager emanager;

protected org.hibernate.Session hibernateSession;

@javax.persistence.PersistenceContext(unitName = "t4Seam")
public void setEntityManager(javax.persistence.EntityManager entityManager) {
    this.emanager = entityManager;
    if (entityManager.getDelegate() instanceof org.hibernate.ejb.HibernateEntityManager) {
        this.hibernateSession = ((org.hibernate.ejb.HibernateEntityManager) entityManager.getDelegate()).getSession();
    }
    else {
       this.hibernateSession = (org.hibernate.Session) entityManager.getDelegate();
    }
}

Hope it will help.