Hibernate 3.0.5
MySQL 4.1.12
Long lived Hibernate session (swing client app)

Every time the user does a save, we close the session and then reopen it, locking all the root objects into the new session (Session.lock() calls). All is fine while navigating the object graph (including lazy collections being fetched on the new session, etc). The trouble starts when we run an HQL that needs to fix up some paths stored in our persisted objects:
"from SomeClass where opPath like somePath" returns the objects we expect (both instances already in the cache as well as instances fetched from the DB). Modifying the path and then saving (from the root objects) generates the NonUniqueObjectException, and breaking at the throw point reveals that there seem to be two instances with the same key, one whose path we updated, and one other instance, same key and the old path.

The code is something like:

Iterator iter = session.createQuery("from Step step where step.opPath like somePath")
.list().iterator();
while(iter.hasNext()) {
Step step = (Step)iter.next();
step.setOperation(null, false);
step.setOpPath(newPath);
session.merge(step);
}

"Save" is simply doing a Session.saveOrUpdate for all roots objects, commiting the long lived transaction (same life span as the session) and then closing the session. Any help is much appreciated.

The exception is:

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session:

at org.hibernate.engine.PersistenceContext.checkUniqueness(PersistenceContext.java:586)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:254)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:214)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:91)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)

at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:468)

at org.hibernate.engine.Cascades$5.cascade(Cascades.java:154)

at org.hibernate.engine.Cascades.cascadeAssociation(Cascades.java:771)

at org.hibernate.engine.Cascades.cascade(Cascades.java:720)

at org.hibernate.engine.Cascades.cascadeCollection(Cascades.java:895)

at org.hibernate.engine.Cascades.cascadeAssociation(Cascades.java:792)

at org.hibernate.engine.Cascades.cascade(Cascades.java:720)

at org.hibernate.engine.Cascades.cascade(Cascades.java:847)

at org.hibernate.engine.Cascades.cascade(Cascades.java:819)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.cascadeOnUpdate(DefaultSaveOrUpdateEventListener.java:316)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:299)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:214)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:91)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)

at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:468)

at org.hibernate.engine.Cascades$5.cascade(Cascades.java:154)

at org.hibernate.engine.Cascades.cascadeAssociation(Cascades.java:771)

at org.hibernate.engine.Cascades.cascade(Cascades.java:720)

at org.hibernate.engine.Cascades.cascadeCollection(Cascades.java:895)

at org.hibernate.engine.Cascades.cascadeAssociation(Cascades.java:792)

at org.hibernate.engine.Cascades.cascade(Cascades.java:720)

at org.hibernate.engine.Cascades.cascade(Cascades.java:847)

at org.hibernate.engine.Cascades.cascade(Cascades.java:819)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.cascadeOnUpdate(DefaultSaveOrUpdateEventListener.java:316)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:299)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:214)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:91)

at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)

at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:468)

at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:463)

.........