[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-6960) NullPointerException in PreCollectionRemove Listener

[Leon Pennings (JIRA)]

    [ https://hibernate.onjira.com/browse/HHH-6960?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=46454#comment-46454 ] 

Leon Pennings commented on HHH-6960:
------------------------------------

I'm added this implementation to our own code as a temporary workaround:

public class EnversPreCollectionRemoveEventListenerImpl
		extends BaseEnversCollectionEventListener
		implements PreCollectionRemoveEventListener {

	protected EnversPreCollectionRemoveEventListenerImpl(AuditConfiguration enversConfiguration) {
		super( enversConfiguration );
	}

	@Override
	public void onPreRemoveCollection(PreCollectionRemoveEvent event) {
        CollectionEntry collectionEntry = getCollectionEntry( event );
        if ( collectionEntry != null && collectionEntry.getLoadedPersister() != null && !collectionEntry.getLoadedPersister().isInverse() ) {
            onCollectionAction( event, null, collectionEntry.getSnapshot(), collectionEntry );
        }
	}
}

Since the nullpointer is occurring on a collectionEntry that is not present in my entity (i.e. it is triggered on a fourth collection where only three collections are present) this workaround is acceptable for now.
Needless to say, the fourth 'phantom' event should never have been fired.
Maybe this is fired by a proxy on the collection?


> NullPointerException in PreCollectionRemove Listener
> ----------------------------------------------------
>
>                 Key: HHH-6960
>                 URL: https://hibernate.onjira.com/browse/HHH-6960
>             Project: Hibernate ORM
>          Issue Type: Bug
>          Components: envers
>    Affects Versions: 4.0.0.Final
>         Environment: Hibernate 4.0.0 to MySQL
>            Reporter: Kevin Jordan
>            Assignee: Gail Badner
>         Attachments: hibernateBugProofWithSchema.zip, hibernateBugProof.zip
>
>
> I'm getting a NullPointerException on line 47 of EnversPreCollectionRemoveEventListenerImpl very consistently. I wasn't sure if it was due to lazy collections or not, but it seems that it fails if they're eagerly fetched or lazily fetched. I'm guessing it has something to do with getLoadedPersister() returning a null value since the comments for it say "This is only available late during the flush cycle". The stack trace is
> Quote:
> java.lang.NullPointerException
> at org.hibernate.envers.event.EnversPreCollectionRemoveEventListenerImpl.onPreRemoveCollection(EnversPreCollectionRemoveEventListenerImpl.java:47)
> at org.hibernate.action.internal.CollectionRemoveAction.preRemove(CollectionRemoveAction.java:143)
> at org.hibernate.action.internal.CollectionRemoveAction.execute(CollectionRemoveAction.java:104)
> at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:273)
> at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:265)
> at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:188)
> at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:323)
> at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52)
> at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1081)
> at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:315)
> at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
> at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175)
> at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:73)
> ... 120 more

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