Hans-

There are only two possible conditions in which I can see this  
problem happening:

1. the class "com.lbslogics.ims.model.PositionLog" is not loadable in  
the current environment's classloader.
2. the PositionLog class was registered with the MetaDataRepository  
during the lookup process.

Since the same code has been executed hundreds of times via the MDB  
prior to this error, neither of these seems very plausible. Are you  
sure that the exact same EntityManagerFactory (in the same JVM) has  
been used prior to this error to execute the same method? The fact  
that it looks like we are parsing the query for the first time (since  
it appears we are making a new internal parse compilation from it)  
makes it look like that particular method has not yet been called for  
that EntityManager's EntityManagerFactory.

If this is something you can reproduce, it would be interesting if we  
could see more logging output (enabled by setting the "kodo.Log"  
property to "DefaultLevel=TRACE"), especially those messages that are  
on the MetaData channel.



On Mar 23, 2007, at 5:57 AM, Hans J. Prueller wrote:

> full stack trace (up until application specific stuff) is:
>
> 2007-03-22 21:34:53,287 : SEVERE : WorkThread-2/34 : Logger.log :
> system exception in business method:
> <4|true|0.9.7-incubating-SNAPSHOT>
> org.apache.openjpa.persistence.ArgumentException: Could not locate
> metadata for the class using alias "PositionLog". Registered alias
> mappings: "{PositionLog=[class com.lbslogics.ims.model.PositionLog]}"
> 	at
> org.apache.openjpa.meta.MetaDataRepository.getMetaData 
> (MetaDataRepository.java:345)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getClassMetaData( 
> JPQLExpressionBuilder.java:164)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.resolveClassMetaD 
> ata(JPQLExpressionBuilder.java:142)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateMetaD 
> ata(JPQLExpressionBuilder.java:211)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateMetaD 
> ata(JPQLExpressionBuilder.java:181)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateType( 
> JPQLExpressionBuilder.java:174)
> 	at org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.access
> $500(JPQLExpressionBuilder.java:61)
> 	at org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder
> $ParsedJPQL.populate(JPQLExpressionBuilder.java:1668)
> 	at
> org.apache.openjpa.kernel.jpql.JPQLParser.populate(JPQLParser.java:52)
> 	at
> org.apache.openjpa.kernel.ExpressionStoreQuery.populateFromCompilation 
> (ExpressionStoreQuery.java:145)
> 	at
> org.apache.openjpa.datacache.QueryCacheStoreQuery.populateFromCompilat 
> ion(QueryCacheStoreQuery.java:237)
> 	at
> org.apache.openjpa.kernel.QueryImpl.newCompilation(QueryImpl.java:644)
> 	at
> org.apache.openjpa.kernel.QueryImpl.compilationFromCache 
> (QueryImpl.java:625)
> 	at
> org.apache.openjpa.kernel.QueryImpl.compileForCompilation 
> (QueryImpl.java:591)
> 	at
> org.apache.openjpa.kernel.QueryImpl.compileForExecutor 
> (QueryImpl.java:653)
> 	at org.apache.openjpa.kernel.QueryImpl.compile(QueryImpl.java:560)
> 	at
> org.apache.openjpa.persistence.EntityManagerImpl.createNamedQuery 
> (EntityManagerImpl.java:785)
> 	at
> org.apache.openjpa.persistence.EntityManagerImpl.createNamedQuery 
> (EntityManagerImpl.java:62)
> 	at com.lbslogics.ims.model.PositionLog.findById(PositionLog.java:175)
> 	at
> com.lbslogics.ims.persistence.ejb.EventBean.getPositionLog 
> (EventBean.java:2875)
>          [ ... some more ]
>
> The corresponding EventBean is a SLSB (EJB2.1) and the method looks  
> like
> that:
>
>         /**
> 	 *
> 	 * @return
> 	 */
> 	public PositionLog getPositionLog(final EntityManager em) {
> 		final PositionLog log = PositionLog.findById(em, getPositionLogId 
> ());
> 		return log;
> 	}
>
> and the Positionlog.findById is a static method which encapsulates  
> some
> of the "technical work":
>
>         public static PositionLog findById(EntityManager em, Long  
> plId)
> {
> 		Query q = em.createNamedQuery("PositionLog.byId");
> 		q.setParameter("id", plId);
>
> 		try {
> 			return (PositionLog) q.getSingleResult();
> 		} catch (javax.persistence.NoResultException e) {
> 			logger.finest("findById: did not find result for id=" + plId);
> 			return null;
> 		}
> 	}
>
> This method or better the top-level entry point of this method is  
> called
> several hundred times for different records, all invoked by a MDB.  
> Could
> it be some concurrency issue because after several hundred invocations
> only a single exception occured?
>
> Hans
>
> Am Freitag, den 23.03.2007, 05:48 -0700 schrieb Patrick Linskey:
>
>> Could you post the full stack trace, and maybe some code showing how
>> you're invoking the JPA APIs?
>>
>> -Patrick
>>