[eclipselink-users] one-to-many: NullPointerException cause rollback

[Antonino Vitale <makete84@xxxxxxxxx>]

Hi everybody,
I'm using Eclipselink as JPA provider for my application.
I have many classes generated from a xml schema using hyperjaxb3.
I have annotations for both jpa and xml elements.
my
 classes have one-to-many relationships, for example a class person has a
 relationship with a class names and a class record has a relationship 
with person etc...
the problem is that i get a nullpointerexception during committing changes to database.
this is the stacktrace:

Exception in thread "main" javax.persistence.

RollbackException: java.lang.NullPointerException
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:102)
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:63)
    at BatchLoadWorldCheck.loadWCLists(BatchLoadWorldCheck.java:428)
    at BatchLoadWorldCheck.main(BatchLoadWorldCheck.java:137)
Caused by: java.lang.NullPointerException
    at org.eclipse.persistence.internal.descriptors.ObjectBuilder.extractValueFromObjectForField(ObjectBuilder.java:2565)[EL Warning]: 2012-04-12 14:58:45.918--UnitOfWork(18164750)--java.lang.NullPointerException

    at org.eclipse.persistence.mappings.OneToManyMapping.updateTargetRowPostInsertSource(OneToManyMapping.java:1337)
    at org.eclipse.persistence.mappings.OneToManyMapping.performDataModificationEvent(OneToManyMapping.java:900)
    at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:157)
    at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:3799)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1415)
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitToDatabase(RepeatableWriteUnitOfWork.java:636)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1505)
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:267)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1143)
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:84)
    ... 3 more

using hibernate as jpa provider all goes well. I thought to move to eclipselink because of a huge number of load operations that in hibernate make my application slower.
if you know the answer, please help me! I'm really confused about this error and I'm new to this kind of things so I can not find solutions.
thank you very much.
bye

Nino