I asked this question a few months ago and never got an answer, hopefully someone can help me out this time. I think the problem I'm having is associated w/ a bug in Hibernate that's been around for a while:

http://opensource2.atlassian.com/projec ... se/HHH-511

I've got a setup where my DAO opens a session & transaction and a servlet filter commits and closes (per the instruction of Hibernate In Action - designing layered applications.)

In doGet() of my servlet I'm fetching an object, populating a form w/ the values (so they can be updated) and setting the object to an HttpSession.

In doPost() I get the object from the session, update the values from the form, and call saveOrUpdate() to persist it.

I call saveOrUpdate because they may be inserting a new record, not just updating an existing one.

This setup means that a session is opened/closed on doGet and another is opened/closed on doPost...so the problem I'm having is re-attaching an existing record on the session being utilized in doPost. Since the object I'm working with has two child objects (which are not mapped in the parent hbm.xml file) - apparently the save or saveOrUpdate methods are seeing the old object, not the new...as outlined in the error report link above.

Occasionally, I get this exception (same as bug report link above):



Sometimes it works and the data is inserted/updated and sometimes it's not...and I get the exception...it's not consistent at all.

I've got several other forms where I use this same setup and it works flawlessly - but that is when working with single objects w/o children of their own.

Any ideas? I would have posted some code but it's long and wrapped up within many layers of my application...and probably wouldn't explain anything that I haven't already.

Hibernate version: 3.1.2

Name and version of the database you are using: MSSQL 2000

/**
* Copy the state of the given object onto the persistent object with the same
* identifier. If there is no persistent instance currently associated with
* the session, it will be loaded. Return the persistent instance. If the
* given instance is unsaved, save a copy of and return it as a newly persistent
* instance. The given instance does not become associated with the session.
* This operation cascades to associated instances if the association is mapped
* with <tt>cascade="merge"</tt>.<br>
* <br>
* The semantics of this method are defined by JSR-220.
*
* @param object a detached instance with state to be copied
* @return an updated persistent instance
*/
public Object merge(Object object) throws HibernateException;

Works beautifully, thanks for the help.

What can I do with the same problem but Hibernate Version 2.1.7?

X

Clear the object from the session then saveOrUpdate().