WebLogic Toplink

In WebLogic we already have TopLink:
$BEA_HOME/modules/com.oracle.toplink_1.0.0.0_11-1-1-3-0.jar
$BEA_HOME/modules/com.oracle.toplinkgrid_1.0.0.0_11-1-1-3-0.jar

Here: http://forums.oracle.com/forums/thread.jspa?messageID=3154042
it says clearly that

Toplink Essentials Provider oracle.toplink.essentials.PersistenceProvider in toplink-essentials.jar

is NOT supported in WebLogic, and we should use the

EclipseLink org.eclipse.persistence.jpa.PersistenceProvider

A jarscan for PersistenceProvider in Weblogic says:

===============================================
Found: PersistenceProvider
Class: kodo.persistence.PersistenceProviderImpl
Package: kodo.persistence
Library Name: com.bea.core.kodo_1.2.0.0_4-2-1.jar
Library Path: C:\bea11\modules\com.bea.core.kodo_1.2.0.0_4-2-1.jar
===============================================

===============================================
Found: PersistenceProvider
Class: javax.persistence.spi.PersistenceProvider
Package: javax.persistence.spi
Library Name: javax.persistence_1.0.0.0_1-0-2.jar
Library Path: C:\bea11\modules\javax.persistence_1.0.0.0_1-0-2.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.apache.openjpa.persistence.PersistenceProviderImpl$1
Package: org.apache.openjpa.persistence
Library Name: org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
Library Path: C:\bea11\modules\org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.apache.openjpa.persistence.PersistenceProviderImpl$ClassTransformerIm
pl$1
Package: org.apache.openjpa.persistence
Library Name: org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
Library Path: C:\bea11\modules\org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.apache.openjpa.persistence.PersistenceProviderImpl$ClassTransformerIm
pl
Package: org.apache.openjpa.persistence
Library Name: org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
Library Path: C:\bea11\modules\org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.apache.openjpa.persistence.PersistenceProviderImpl
Package: org.apache.openjpa.persistence
Library Name: org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
Library Path: C:\bea11\modules\org.apache.openjpa_1.1.0.0_1-1-1-SNAPSHOT.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.eclipse.persistence.jpa.PersistenceProvider
Package: org.eclipse.persistence.jpa
Library Name: org.eclipse.persistence_1.0.0.0_2-0.jar
Library Path: C:\bea11\modules\org.eclipse.persistence_1.0.0.0_2-0.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.eclipse.persistence.jpa.osgi.PersistenceProvider
Package: org.eclipse.persistence.jpa.osgi
Library Name: org.eclipse.persistence_1.0.0.0_2-0.jar
Library Path: C:\bea11\modules\org.eclipse.persistence_1.0.0.0_2-0.jar
===============================================

===============================================
Found: PersistenceProvider
Class: javax.persistence.spi.PersistenceProvider
Package: javax.persistence.spi
Library Name: wsclient_extended.jar
Library Path: C:\bea11\oracle_common\webservices\wsclient_extended.jar
===============================================

===============================================
Found: PersistenceProvider
Class: org.eclipse.persistence.jpa.PersistenceProvider
Package: org.eclipse.persistence.jpa
Library Name: wsclient_extended.jar
Library Path: C:\bea11\oracle_common\webservices\wsclient_extended.jar
===============================================

so the best candidate seems

C:\bea11\modules\org.eclipse.persistence_1.0.0.0_2-0.jar


IF you want to use Toplink Essentials, follow this path:
http://debupanda.blogspot.com/2008/03/using-toplink-essentials-as-jpa.html