Problems with persistence jars

Question

Hello.

I'm struggling with JBOss and I'm stuck on a problem which seems trival to fix but it turns out I can't. When I try to deploy a simple java web app I encounter an exception:

org.hibernate.ejb.HibernatePersistence cannot be cast to avax.persistence.spi.PersistenceProvider

I know that this is a problem with having more then one persistence.jar. So in my pom I did something like that:

<dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>3.4.0.GA</version>
            <exclusions>
                <exclusion>
                    <groupId>org.hibernate</groupId>
                    <artifactId>ejb3-persistence</artifactId>
                </exclusion>
</dependency>

But I'm unlucky with it. I still get the error. Could anybody help me kindly to solve this task?

Agata

Answer 1

It looks like you want to package your own version of Hibernate within your application. This is possible but you'll have to setup classloader scoping for your application. From ClassLoadingConfiguration:

Isolation with Overriding Server Classes

Use the following constructs to enabled scoped class loading with the deployment classes overriding the server classes.

...

For jboss-web.xml:

<jboss-web>
   <class-loading java2ClassLoadingCompliance="false">
      <loader-repository>
         com.example:archive=unique-archive-name
         <loader-repository-config>java2ParentDelegation=false</loader-repository-config>
      </loader-repository>
   </class-loading>
 ...

In other words, either include all your Hibernate libraries and disable parent class loader delegation or exclude them all and use the one from JBoss.

See also

• http://community.jboss.org/wiki/JBossClassLoadingUseCases
• http://community.jboss.org/wiki/ClassLoadingConfiguration