NPE while trying to use field-based Optimistic Locking with Level2 Cache disabled

[rm3l]

Hi there!

I tried to enable field-based Optimistic Locking (using a Version-annotated field), but could not get it to work with DataNucleus. It ends up with an NPE along with the following message: Exception thrown while loading remaining rows of query
See the stack trace below and the datanucleus.log file.

Looking into the persistence unit properties, I located the culprit: disabling the Level2 Cache (via the 'datanucleus.cache.level2.type' property) does cause the error. It works when I set it to any other type: soft or weak.

For reference, I tested the same case against other JPA Providers (EclipseLink and Hibernate) via different Maven Profiles and the test does pass as expected.

Is not being able to use Optimistic Locking without an L2 Cache an intended behavior? Or am I missing something?

A test case is available in this Git repo: https://github.com/rm3l/dn-issue-optimistic-locking-jpa

Stacktrace:

15:27:33,298 (main) ERROR [DataNucleus.General] - >> Exception in operation execution                                                                                                               
java.lang.NullPointerException                                                                                                                                                           
        at org.datanucleus.store.rdbms.fieldmanager.ResultSetGetter.fetchLongField(ResultSetGetter.java:115)                                                                                                      
        at org.datanucleus.state.StateManagerImpl.replacingLongField(StateManagerImpl.java:1924)                                                                      
        at mydomain.model.AbstractBaseJpaEntity.dnReplaceField(AbstractBaseJpaEntity.java)                                                                                                                        
        at mydomain.model.AbstractIdentifiable.dnReplaceField(AbstractIdentifiable.java)                                                                                                                          
        at mydomain.model.Person.dnReplaceField(Person.java)                                                                                                                                                      
        at mydomain.model.AbstractBaseJpaEntity.dnReplaceFields(AbstractBaseJpaEntity.java)                                                                                                                       
        at org.datanucleus.state.StateManagerImpl.replaceFields(StateManagerImpl.java:4290)                                                                                                                       
        at org.datanucleus.state.StateManagerImpl.replaceFields(StateManagerImpl.java:4315)                                                                                                                      
        at org.datanucleus.store.rdbms.request.FetchRequest.execute(FetchRequest.java:419)                                                                                                                        
        at org.datanucleus.store.rdbms.RDBMSPersistenceHandler.fetchObject(RDBMSPersistenceHandler.java:316)                                                                                                      
        at org.datanucleus.state.StateManagerImpl.loadFieldsFromDatastore(StateManagerImpl.java:1512)                                                                                                             
        at org.datanucleus.state.StateManagerImpl.loadUnloadedFieldsInFetchPlan(StateManagerImpl.java:3867)                                                                                                       
        at org.datanucleus.store.rdbms.mapping.java.PersistableMapping.getObject(PersistableMapping.java:780)                                                                                                     
        at org.datanucleus.store.rdbms.fieldmanager.ResultSetGetter.fetchObjectField(ResultSetGetter.java:176)                                                                                                    
        at org.datanucleus.state.StateManagerImpl.replacingObjectField(StateManagerImpl.java:1965)                                                                                                                
        at mydomain.model.Address.dnReplaceField(Address.java)                                                                                                                                              
        at mydomain.model.AbstractBaseJpaEntity.dnReplaceFields(AbstractBaseJpaEntity.java)                                                                                                                       
        at org.datanucleus.state.StateManagerImpl.replaceNonLoadedFields(StateManagerImpl.java:4343)                                           
        at org.datanucleus.store.rdbms.query.PersistentClassROF$1.fetchNonLoadedFields(PersistentClassROF.java:507)                                                                                 
        at org.datanucleus.ExecutionContextImpl.findObject(ExecutionContextImpl.java:3214)                                                                                                                        
        at org.datanucleus.store.rdbms.query.PersistentClassROF.findObjectWithIdAndLoadFields(PersistentClassROF.java:476)                                                                                        
        at org.datanucleus.store.rdbms.query.PersistentClassROF.getObject(PersistentClassROF.java:382)                                                                                                            
        at org.datanucleus.store.rdbms.fieldmanager.ResultSetGetter.processSubObjectFields(ResultSetGetter.java:222) 

[andyjefferson]

Can't reproduce with provided test and current codebase