CWWJP0009E error when creating persistence unit

Question

I was facing the following error when starting my Java EE application in IBM WebSphere Application Server WAS 7.

JPAPUnitInfo E CWWJP0009E: The server cannot create an EntityManagerFactory factory for the NAME_OF_THE_PERSISTENCE_UNIT persistent unit from the org.hibernate.ejb.HibernatePersistence provider in file:/C:/PATH/TO/APPLICATION/target/classes/ module.

There is certainly something broken in the definition of your persistence unit. You may find the configuration in your persistence.xml file. To get more detailed information you have to enable tracing for the server's JPA support.

Answer 1

Enable tracing in WAS for JPA

From the main menu of the Application Server's Admin Console choose:

1. Troubleshooting
2. Logs and trace
3. Your server
4. Change log detail levels
5. Switch to one of the two tabs:
   • "Configuration" for a durable change, which are effective after restart
   • "Runtime" for immediately active changes, which are reverted after restart
6. Add messages of all severities from com.ibm.ws.jpa.*

Your final trace configuration could look like this:

*=info: com.ibm.ws.jpa.*=all

This may be active immediately or after restart, depending on your choice above.

Now you find the information to be logged in the server's trace.log file, which is stored in the server's log directory. E.g.

C:\IBM\SDP\runtimes\base_v7\profiles\AppSrv01\logs\server1

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Solution

The cause of your problem may vary widely. So you have to rely on the diagnosis of your trace file.

However, in my situation I found the following there:

JPAPUnitInfo 3 Caught unexpected exception:org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.acme.Class1.prop2[com.acme.Class2]

It could be helpful for you, to look out for an AnnotationException too. In my case, I added Class2 to the PU definition in my persistence.xml. That worked.

Good luck folks ;-)