Hi

While using unidirectional one to many associations ( using a set ), we are getting error as :
org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions during update operation ( after doing a select using the same session ) .

Please let me know the reason to this & solution ASAP.

Thanks
Nisha

You are managing your Hibernate sessions incorrectly in your program. That set should be modified in the context of the same session from which you obtained it. Don't manipulate that set elsewhere and then try to reinsert it into the parent object, for example, Hibernate won't allow that.

How do you obtain your Hibernate sessions?
Can you post the code that obtains the parent object, and the code that uses the set?

This is my utility class used to obtain hibernate session.

package financing.tools.dgs.ws.hibDB;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import javax.naming.InitialContext;
import javax.naming.NamingException;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class HibernateUtility{
private static final SessionFactory sessionFactory;

static {
try {
// Create the SessionFactory from hibernate.cfg.xml
sessionFactory = new Configuration().configure().buildSessionFactory();

} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}


public HibernateUtility(){

}



public static SessionFactory getSessionFactory() {
return sessionFactory;
}


public void insert(Object beanClass){
Session session = getSessionFactory().openSession();
session.save(beanClass);

}

public void update(Object bean){
Session session = getSessionFactory().openSession();
session.merge(bean);
session.flush();

}

public Object select(Serializable uniqueIdentifier,Class beanclass){
Object beanObject = null;
Session session = getSessionFactory().getCurrentSession();
beanObject =session.load(beanclass, uniqueIdentifier);
session.flush();
return beanObject;
}

public void delete(Object beanClass){
Session session = getSessionFactory().getCurrentSession();
session.delete(beanClass);
session.flush();
}

public Object select1(Serializable uniqueIdentifier,Class beanclass){
Object beanObject = null;
Session session = getSessionFactory().openSession();
beanObject =session.get(beanclass, uniqueIdentifier);
session.flush();
return beanObject;
}




}




Now i am calling this utility in my HandlerHibernate class code.The snippet of calling utility class is pasted here. I am using JTA transaction for this.

UserTransaction tx = (UserTransaction)new InitialContext()
.lookup("java:comp/UserTransaction");
try{
tx.begin();
weblog1 = (Weblog)hb.select1(uniqueKey, Weblog.class) ;
hb.delete(weblog1);
tx.commit();
}catch(RuntimeException e){
tx.rollback();
e.printStackTrace();
}

The problem is that you want to have a contextual sessions bound to the jta transaction but use inappropriate SessionFactory method for that.

Just use getSessionFactory().getCurrentSession() instead of getSessionFactory().openSession() at select1().

Denis is correct. If you open a fresh session every time, the new session doesn't know about the session that had previously retrieved your set.