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From Marina Vatkina <Marina.Vatk...@Sun.COM>
Subject Re: AW: Forgot subject: Strange Could not locate metadata for the classError?
Date Fri, 23 Mar 2007 21:56:21 GMT
Marc,

No, in GlassFish (GF) it shouldn't be the case, but there could be more than 1 
EMF created at the same time. The test case uses stateless session bean for 
accessing EM, so there is no guarantee that the same bean instance serves the 
1st method (with a successful persist) and the 2nd (with a failed query). But 
what's worth noting, that in both cases, mine and Hans's it's the query that 
causes the problems).

BTW, I need to test again without tracing - it can slow things down and hide the 
problem.

regards,
-marina

Marc Prud'hommeaux wrote:
> Marina-
> 
> In a normal J2EE app, the same EntityManager will never be used  
> concurrently from multiple threads. That might also be the case in  your 
> environment, but it would be interesting to see if the problem  ever 
> crops up after you enable this property.
> 
> 
> 
> On Mar 23, 2007, at 2:36 PM, Marina Vatkina wrote:
> 
>> Marc,
>>
>> Does OpenJPA figures out by itself that it is running in a  
>> multithreaded environment when used in an app- or web-server? Or do  
>> you expect users to always specify this setting when they decide to  
>> deploy it to a multi-threaded container?
>>
>> thanks,
>> -marina
>>
>> Marc Prud'hommeaux wrote:
>>
>>> Hans-
>>> I don't see how the error could be data-related.
>>> One thing: if you are using the same EMF from multiple threads,  do  
>>> you have the "openjpa.Multithreaded" property explicitly set  to  
>>> "true" in your persistence.xml (or however you are configuring  the  
>>> EMF)? Failure to do this means that access to the broker is   
>>> unsynchronized, and I can see how it might lead to a problem like  this.
>>> On Mar 23, 2007, at 11:46 AM, Hans J. Prueller wrote:
>>>
>>>> hm.. sounds strange. could it bet he case that the error message   
>>>> openjpa is
>>>> printing is only a subsequent error of another one below/before?
>>>>
>>>> as the JNDI binding did not really work (as you can remember:   
>>>> everytime I am
>>>> accessing the EMF from JNDI it is initialized again and again) so  
>>>> I  did a
>>>> quick-and-dirty solution for the PoC of OpenJPA integration: I   
>>>> saved the EMF
>>>> as a static field instead to JNDI, i.e. the first time it is   
>>>> accessed it is
>>>> created - then every client throughout my app should access the   
>>>> same static
>>>> EMF instance. As there is definitely only a single JVM this   
>>>> shouldn't make
>>>> problems I suggest...
>>>>
>>>> Additionally I did not see any data in the logs that is  indicating  
>>>> that a
>>>> second EMF is initialized or sth. like that. The strange thing  is  
>>>> that it
>>>> worked several invocations before and after .. could it be a  data- 
>>>> related
>>>> problem? Anyway, I was not able to reproduce the error....
>>>>
>>>> Hans
>>>>
>>>>
>>>>
>>>>
>>>>> -----Ursprüngliche Nachricht-----
>>>>> Von: Marc Prud'hommeaux [mailto:mprudhomapache@gmail.com] Im   
>>>>> Auftrag von
>>>>> Marc Prud'hommeaux
>>>>> Gesendet: Freitag, 23. März 2007 17:59
>>>>> An: open-jpa-dev@incubator.apache.org
>>>>> Betreff: Re: Forgot subject: Strange Could not locate metadata  
>>>>> for  the
>>>>> classError?
>>>>>
>>>>> 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.getClassMetaD

>>>>>> at a(
>>>>>> JPQLExpressionBuilder.java:164)
>>>>>>     at
>>>>>> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.resolveClassM

>>>>>> et aD
>>>>>> ata(JPQLExpressionBuilder.java:142)
>>>>>>     at
>>>>>> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateM

>>>>>> et aD
>>>>>> ata(JPQLExpressionBuilder.java:211)
>>>>>>     at
>>>>>> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateM

>>>>>> et aD
>>>>>> ata(JPQLExpressionBuilder.java:181)
>>>>>>     at
>>>>>> org.apache.openjpa.kernel.jpql.JPQLExpressionBuilder.getCandidateT

>>>>>> yp e(
>>>>>> 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.populateFromCompila

>>>>>> ti on
>>>>>> (ExpressionStoreQuery.java:145)
>>>>>>     at
>>>>>> org.apache.openjpa.datacache.QueryCacheStoreQuery.populateFromComp

>>>>>> il at
>>>>>> 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
>>>>>>>
>>>>
>>
> 
> 


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