If you are looking to use Hibernate JPA with Weblogic 10 then there are a couple of things to keep in mind
1. OpenJPA is the default JPA provider in weblogic so if you don’t get the configuration right then you should be seeing errors related to Open JPA
2. Even if you have hibernate jars within your EAR or WAR you may see them work. Again, this relates to point 1. So you have to tell weblogic to make use of Hibernate jars. One way to do it is to place the hibernate and its related jars under the server lib folder so that these jars are loaded upfront. There is another way where you use the deployment descriptor to indicate that weblogic should prefer the jars deployed with the application.