Hi,
I have couple of Questions using ThreadLocal in J2EE server deployment.

1. Whats the recommended way of managing hibernate session, I mean, is it OK to use ThreadLocal to get the session object.

2. I am currently using ThreadLocal to get my Session and having the following error.

Code giving the session

public static Session currentSession() throws DaoException {
Session s = (Session) threadLocal.get();
try {
if(s == null) {
if (sf == null) {
try {
loadClasses();
sf = cfg.buildSessionFactory();
}
catch(Exception e) {
System.err.println("%%%% Error Creating SessionFactory %%%%");
e.printStackTrace();
}
}
s = sf.openSession();
threadLocal.set(s);
}
}
catch (HibernateException he) {
throw new DaoException(he);
}
return s;
}

my DAO has methods like this:

public Location getLocationByPk(String locId) throws DaoException {
Location loc = null;
Session sess = getSession();
try {
loc = (Location) sess.get(Location.class, locId);
return loc;
} catch (HibernateException e) {
throw new DaoException("Error Creating Query: getLocationByPk() " + e.getMessage());
} finally {
closeSession(sess);
}
}

public State getStateByPk(String stateId) throws DaoException {
Session sess = getSession();
State loc = null;
try {
loc = (State) sess.get(State.class, stateId);
return loc;
} catch (HibernateException e) {
throw new DaoException("Error Creating Query: getStateByPK() " + e.getMessage());
} finally {
closeSession(sess);
}
}


public static void main(String[] args) {
try {
Location temp = dao.getLocationByPk("HQ");
State st = dao.getStateByPk("NV");
temp.setStateId("NV");
dao.updateLocation(temp);
} catch (DaoException e) {
e.printStackTrace();
}
}

Giving the error after executing the first getLocationByPK();
net.sf.hibernate.HibernateException: Session is closed
at net.sf.hibernate.impl.SessionImpl.connection(SessionImpl.java:3250)
at net.sf.hibernate.impl.BatcherImpl.prepareQueryStatement(BatcherImpl.java:65)
at net.sf.hibernate.loader.Loader.prepareQueryStatement(Loader.java:704)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:185)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:831)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:851)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:57)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:49)
at net.sf.hibernate.persister.EntityPersister.load(EntityPersister.java:419)
at net.sf.hibernate.impl.SessionImpl.doLoad(SessionImpl.java:2081)
at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:1955)
at net.sf.hibernate.impl.SessionImpl.get(SessionImpl.java:1891)

My question is:
1.Do I need to close the session at all in the methods..?
2. Is it a problem thats arising because of ThreadLocal..?


Thanks

If you use this implem of TLS you should not close the session inside sub methods (only the first one)
To prevent that you can use a counter inside the TLS to implement fake close and keep your code coherent.