Hello, I've a problem in a method that advance in a definition process for the indicated transition. The method is the following:

private void goTo(Long id_instance, String transition) {
 try {
 ProcessInstance instance=getJbpmContext().loadProcessInstanceForUpdate(id_instance);
 if(!instance.isTerminatedImplicitly()){
 Token token=new Token(instance);
 token.signal(transition);

 jbpmContext.save(token);
 jbpmContext.save(instance);
 }
 } catch (RuntimeException e) {
 e.printStackTrace();
 }finally{
 jbpmContext.close();
 }
 }

And the exception is.

12:40:42,078 ERROR [DbPersistenceService] hibernate commit failed
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: org.jbpm.graph.exe.Token
 at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:219)
 at org.hibernate.type.EntityType.getIdentifier(EntityType.java:397)
 at org.hibernate.type.ManyToOneType.isDirty(ManyToOneType.java:242)
 at org.hibernate.type.TypeFactory.findDirty(TypeFactory.java:597)
 at org.hibernate.persister.entity.AbstractEntityPersister.findDirty(AbstractEntityPersister.java:3123)
 at org.hibernate.event.def.DefaultFlushEntityEventListener.dirtyCheck(DefaultFlushEntityEventListener.java:479)
 at
....

How could do I fix it?? Because I save both, token and instance. I tried only to save the instance but it didn't work.

Thanks