When to close session on a J2EE application

stianwest · **Joined:** Thu Feb 22, 2007 6:44 am **Posts:** 3

In our J2EE application, should we everytime we perform a hibernate request close the session? For instance, should we close it in the finally block, like in this code:

Code:

public KategoriData getKategoriById(String id) throws BaatkatalogenException {
   if (id == null)
       throw new BaatkatalogenException("id er null");

   Session session = HibernateUtil.getSessionFactory().getCurrentSession();
   session.beginTransaction();
   Criteria criteria = session.createCriteria(KategoriData.class);
   criteria.add(Expression.eq("id", id));
   criteria.setMaxResults(1);
   try {
       return (KategoriData) criteria.uniqueResult();
   } catch (HibernateException e) {
       throw new BaatkatalogenException ;
   } finally {
       if(session.isOpen()) {
      session.close();
       }
   }
    }

If not, then when should we close it?

Because I dont know when the user is finished using the application. I am using c3p0, and I have defined idle time period and timeout, will that result in closing the sessions when the idle time is finished?

scesbron · **Joined:** Thu Sep 04, 2003 8:23 am **Posts:** 368

Maybe you can use opensessioninviewfilter then your session will be close after your view is rendered if you are in a web based environment

Another way of doing is using a framework to handle transactions like Spring or EJB3 container. Thus this container will handle session management

Ananasi · **Posted:** Fri Mar 16, 2007 10:59 am

BTW, if you need to load an object by id, use the get() or load() method instead of issuing a query (where you could use Restrictions.idEq() method instead of the Expression.eq()) and then setting maxResults to one (better off fetching unique results with the uniqueResult() method instead of the list() method/maxResults pairing).

Did not know if it was just an example you made up or if that was real production code.

swaldman · **Joined:** Tue Jan 06, 2004 8:58 pm **Posts:** 145

Quote:

I am using c3p0, and I have defined idle time period and timeout, will that result in closing the sessions when the idle time is finished?

c3p0's idle test period and timeout/maxIdleTime only affect Connections in the pool and not checked out. Connections associated with a hibernate Session are, from c3p0's perspective, checked out of the pool and in use by the client application.

c3p0 is written at a lower level than hibernate -- it doesn't know anything about Sessions. Your application should clean up the Sessions it works with -- the pool can't and won't do it for you, except in unusual circumstances and very rough ways (e.g. destroying Connections it considers leaked owing to an unreturnedConnectionTimeout).

good luck!

Steve