I have:

public Collection xxx(String username) {

Session session = HibernateUtil.currentSession();
Transaction tx = session.beginTransaction();
query = session.createQuery("...");

Collection resultList=query.list();


tx.commit();
HibernateUtil.closeSession();
return resultList;
}

But I get nothing returned, I guess it's because i close the session. I don't know when would be the best time to close a session and how to detach a object/collection. can someone help me ?

or you can iterate over the collection before you close the session. There may be other ways, not sure.

sounds not a best way to do it. is there anyway like JDO does ses.attach/detach...?

try lazy=false. If you have lazy=true, the session will not populate your objects in the collection util you access them. If you don't use lazy=true, you have to iterate over them to get get hibernate to populate them.

liudan, everything is fine with session closing, the same approach works for me and collection returned by query.list() does not expire after session.close(). Check yor query: look into the hibernate debug level log, copy SQL query for your HQL one, repalce all ? with the corresponding values and execute this SQL query using your SQL tool, I guess it returns nothing.

Leonid

I have not heard anything about attache/detach in Hibernate. About collections and objects returned by Hibenate query.list() I already thought like about detached ones.

session.lock(object, LockMode.NONE)
or session.update() if the object may be dirty.