OutOfMemoryError/Not closing pre-bound Hibernate Session...

beejal27 · **Joined:** Mon Sep 26, 2005 8:43 am **Posts:** 16

I am in the process of Upgrading Hibernate from version 2.1.6 to 3.0.5. Well as we are making use of Spring Framework, we are also upgrading Spring from version 1.0.1 to 1.2.4 (as it supports Hibernate 3). What I have observed is: After certain DB calls the application is not working and showing java.lang.OutOfMemoryError. When I observe the stack trace it shows that the Session objects are not being closed:

Code:

2005-10-19 10:40:16,689 DEBUG [com.abc.persistence.MyHibernateTemplate] Found thread-bound Session for HibernateTemplate
2005-10-19 10:40:19,513 DEBUG [com.abc.persistence.MyHibernateTemplate] Eagerly flushing Hibernate session
2005-10-19 10:40:19,513 DEBUG [com.abc.persistence.MyHibernateTemplate] Not closing pre-bound Hibernate Session after HibernateTemplate

The code for MyHibernateTemplate is as follows:

Code:

import org.hibernate.FlushMode;
import org.hibernate.HibernateException;
import org.hibernate.Session;

import org.springframework.orm.hibernate3.HibernateTemplate;

public class MyHibernateTemplate extends HibernateTemplate
{
   /**
    * @see org.springframework.orm.hibernate3.HibernateAccessor#flushIfNecessary(org.hibernate.Session, boolean)
    */
   public void flushIfNecessary(Session session, boolean existingTransaction)
         throws HibernateException
   {
      // Overriden to prevent flushing if Session.flushMode is NEVER      
      boolean assumeReadOnlyTransaction = existingTransaction && session.getFlushMode().equals(FlushMode.NEVER);
      
      if( !assumeReadOnlyTransaction )
      {
         super.flushIfNecessary(session, existingTransaction);
      }
   }
}

Well, I am not very sure whether this problem is due to Spring or Hibernate. But it used to work in the earlier Spring & Hibernate. Plz. let me know what's going wrong.

kgignatyev · **Posted:** Wed Oct 19, 2005 2:52 am

my 2c :do not use HibernateTemplate, configure Spring to inject H callbacks and wrap your object into Spring's transaction context support.
http://www.onjava.com/lpt/a/5854
http://www.springframework.org/docs/reference/orm.html

beejal27 · **Joined:** Mon Sep 26, 2005 8:43 am **Posts:** 16

Hello Konstantin,

kgignatyev wrote:

my 2c :do not use HibernateTemplate, configure Spring to inject H callbacks

Can you please let me know the reason for the above statement. The reason behind this question is : We are making use of HibernateTemplate throughout the application and if we act on your suggestion it would lead to a very big change (Which should be considered as last option only).

Quote:

and wrap your object into Spring's transaction context support.

We already have implemented AOP feature of Spring (org.springframework.transaction.interceptor.TransactionInterceptor) to wrap certain objects with Spring Transaction context.

Quote:

http://www.onjava.com/lpt/a/5854
http://www.springframework.org/docs/reference/orm.html

Have you provided these links for guiding regarding Making use of Spring Transaction or do u want to convey some more information also by this links?

kgignatyev · **Posted:** Wed Oct 19, 2005 11:07 am

Quote:

Can you please let me know the reason for the above statement. The reason behind this question is : We are making use of HibernateTemplate throughout the application and if we act on your suggestion it would lead to a very big change (Which should be considered as last option only).

http://houseofhaug.net/blog/archives/20 ... tes-spring

I do not thing you will need that much of refactoring especially because you already have the transaction interceptor in place. Basically instead of using H template you will have your DAO objects as simple POJOs with a setter method for H session and then you will use the session directly for everything you need. I would say that the change is trivial.

And the two links I mentioned:
Spring documentation link: as a reference for various spring provided methods of dealing with Hibernate.
Article link: detailed example of using H in Spring as I suggest using it.