Re: [eclipselink-users] NullPointerException in PersistenceObjectAttribu

[Laird Nelson <ljnelson@xxxxxxxxx>]

I noticed that too; simple bug; should have been t.freeResponseIds.

The query itself is actually dynamic and the table name is supplied at query build time.  The intent is to turn this native query into a set of entities, which works fine.

(There is a set of tables in my application that are under the control of the user; they all share these fields in common.  Through various gyrations of the app, the user can pick which table to build normalized entities out of; this native query gets assembled from the table name.  So a simple entity mapping doesn't work, because the table name is not known at compile/startup time.)

I'll keep an eye on this and see if I can narrow down what I was doing when it happens again.  I cannot reproduce this in a unit test (I've tried, believe me).

Best,
Laird

On Mon, Jan 10, 2011 at 9:39 AM, Tom Ware <tom.ware@xxxxxxxxxx> wrote:

This exception seems to occur when trying to set a value in a null object.  I am not sure what would cause EclipseLink to try to do that.  Can you provide any other information about what is occuring?

I notice that your example query selects "freeResponseIds" but does not link it to anything else in your query. (i.e. you select t.id, t.text with "t." but freeResponseIds without the "t.") What is the goal here?

-Tom

Laird Nelson wrote:

I have an application that runs a simple JPA native query.  99 out of 100 times the query works fine.  Then every now and again I get this:

Caused by: java.lang.NullPointerException
   at org.eclipse.persistence.internal.descriptors.PersistenceObjectAttributeAccessor.setAttributeValueInObject(PersistenceObjectAttributeAccessor.java:46)
   at org.eclipse.persistence.mappings.DatabaseMapping.setAttributeValueInObject(DatabaseMapping.java:1426)
   at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1317)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:343)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.refreshObjectIfRequired(ObjectBuilder.java:3333)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildWorkingCopyCloneFromRow(ObjectBuilder.java:1495)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObjectInUnitOfWork(ObjectBuilder.java:559)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:496)
   at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:455)
   at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:723)
   at org.eclipse.persistence.queries.ReadAllQuery.registerResultInUnitOfWork(ReadAllQuery.java:743)
   at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:424)
   at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1080)
   at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:808)
   at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1040)
   at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:384)
   at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1126)
   at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2904)
   at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1508)
   at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1490)
   at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1464)
   at org.eclipse.persistence.internal.jpa.EJBQueryImpl.executeReadQuery(EJBQueryImpl.java:484)
   at org.eclipse.persistence.internal.jpa.EJBQueryImpl.getResultList(EJBQueryImpl.java:741)

Once the query has failed in this manner, it will continue to fail until application restart.

I am using the EclipseLink version that is bundled with Glassfish 3.1b36.

My query is SELECT t.id <http://t.id> AS ID, 'FreeResponse' AS ANSWERSETNAME, t.text AS TEXT, freeResponseIds AS FREERESPONSEIDS FROM FreeResponse t

What is EclipseLink trying to tell me here?

Thanks,
Laird

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