StaleObjectStateException while executing a jBPM process containing a fork/join on SOA-P.

Issue

• Executing a jBPM process with a fork fails with the following exception:

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.context.exe.ContextInstance#123]
        at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1782)
        at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2425)
        at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2325)
        at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2625)
        at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:115)
        at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:278)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:262)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
        at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
        at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
        at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1030)
        at org.jboss.soa.esb.services.jbpm.integration.command.AbstractMessageListener.onMessage(AbstractMessageListener.java:77)
        at org.jboss.soa.esb.services.jbpm.integration.command.JobListener.onMessage(JobListener.java:16)

• The race condition is sometimes happening on ContextInstance, sometimes on TokenVariableMap.