Logging Optimistic Concurrency Exceptions: org.hibernate.StaleObjectStateException and JBPM

When it is running in a cluster configuration, the jBPM synchronizes with the database by using optimistic locking. This means that each operation is performed in a transaction and if, at the end, a collision is detected, then the transaction in question is rolled back and has to be handled with a retry. This can cause org.hibernate.StateObjectStateException exceptions. When this happens, Hibernate will log the exceptions with a simple message: optimistic locking failed

Hibernate can also log the StateObjectStateException with a stack trace:

15:35:07,123 [DispatcherThread] ERROR [AbstractFlushingEventListener] Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [org.jbpm.pvm.internal.job.TimerImpl#960071]
 at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1769)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2412)
 at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2312)
 at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2612)
 at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:96)
 at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
 at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
 at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
 at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
 at org.jbpm.pvm.internal.tx.HibernateSessionResource.prepare(HibernateSessionResource.java:56)
 at org.jbpm.pvm.internal.tx.StandardTransaction.commit(StandardTransaction.java:107)
 at org.jbpm.pvm.internal.tx.StandardTransaction.complete(StandardTransaction.java:64)
 at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:57)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
 at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)
 at org.jbpm.pvm.internal.svc.SkipInterceptor.execute(SkipInterceptor.java:43)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.acquireJobs(DispatcherThread.java:126)
 at org.jbpm.pvm.internal.jobexecutor.DispatcherThread.run(DispatcherThread.java:67)

To remove these stack traces, set the org.hibernate.event.def.AbstractFlushingEventListener class to FATAL. Do so in log4j by using the following configuration:

log4j.logger.org.hibernate.event.def.AbstractFlushingEventListener=FATAL

Remember, this exception will not affect your process execution!, you can ignore it :)

Source: http://docs.redhat.com/docs/en-US/JBoss_Enterprise_SOA_Platform/5/html/JBPM_Reference_Guide