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Rode
 Post subject: Session not closing properly?
PostPosted: Sun Feb 28, 2010 7:13 pm 
Newbie

Joined: Thu Feb 25, 2010 11:09 am
Posts: 7
Hi, I just got hibernate working but I have a problem. It only works for a while then I get the "Cannot open connection".
I can only assume that the sessions are not closing and finally it gets too many?
I made a simplified example to illustrate.

Code:
public class HQLGroupByExample {
   
   public static void main(String[] args) {
      for (int i=0; i<125; i++){
         func();
      }
   
   }
   
   public static void func(){
      Session session = null;
      try {
         // This step will read hibernate.cfg.xml and prepare hibernate for
         // use
         SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
         session = sessionFactory.openSession();
         //Group By Clause Example
          Transaction tx = session.beginTransaction();
         String SQL_QUERY = "select sum(insurance.investementAmount),insurance.insuranceName "
            + "from Insurance insurance group by insurance.insuranceName";
         Query query = session.createQuery(SQL_QUERY);
         for (Iterator it = query.iterate(); it.hasNext();) {
            Object[] row = (Object[]) it.next();
            //   System.out.println("Invested Amount: " + row[0]);
            System.out.println("Insurance Name: " + row[1]);
         }
          tx.commit();
         
      } catch (Exception e) {
         System.out.println(e.getMessage());
      } finally {
         session.close();
      }
   }



The loop works for maybe a hundred runs or so and then it doesn't.
Anyone knows how to make it work?
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SIau_Tie
 Post subject: Re: Session not closing properly?
PostPosted: Mon Mar 01, 2010 1:27 am 
Senior
Senior

Joined: Wed Sep 19, 2007 9:31 pm
Posts: 191
Location: Khuntien (Indonesia)
Hmm, do not call SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory() many times, just load it first time. Try to call getCurrentSession() instead of openSession().
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Rode
 Post subject: Re: Session not closing properly?
PostPosted: Mon Mar 01, 2010 9:05 am 
Newbie

Joined: Thu Feb 25, 2010 11:09 am
Posts: 7
SIau_Tie wrote:
Hmm, do not call SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory() many times, just load it first time. Try to call getCurrentSession() instead of openSession().



Hi thanks for your reply.
I accidently posted this twice and now I got replies in both threads.
Anyway I will look into your reply too =)


Strangely enough that methods seems to be missing for me. It says
"The method getCurrentSession() is undefined for the type SessionFactory"

OK, wrong version of hibernate3.jar. When I changed it for a newer one, it did find getCurrentSession() but none of the examples work.
They just say

Exception in thread "main" java.lang.NullPointerException
at roseindia.tutorial.hibernate.HQLGroupByExample.func(HQLGroupByExample.java:56)
at roseindia.tutorial.hibernate.HQLGroupByExample.main(HQLGroupByExample.java:28)

Does anyone know exactly which jars I need to make it work and where to get them?
I went to https://www.hibernate.org/6.html but there are just so overwhelmingly many different downloads there and not much information about what is what as far as I can see.
Anyone? I'm really confused about this.
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Rode
 Post subject: Re: Session not closing properly?
PostPosted: Mon Mar 01, 2010 10:06 am 
Newbie

Joined: Thu Feb 25, 2010 11:09 am
Posts: 7
Ok, I downloaded hibernate-distribution-3.3.2.GA

Made a new project in eclipse and added the jars under
hibernate-distribution-3.3.2.GA\lib\required

slf4j-api-1.5.8.jar
jta-1.1.jar
javassist-3.9.0.GA.jar
dom4j-1.6.1.jar
commons-collections-3.1.jar
antlr-2.7.6.jar

and I also added

hibernate3.jar

I have the following example code that worked with the old jars.

Code:
package roseindia.tutorial.hibernate;



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


/**
* @author Deepak Kumar
*
* http://www.roseindia.net
* Hibernate example to inset data into Contact table
*/
public class FirstExample {
   public static void main(String[] args) {
      Session session = null;

      try{
         // This step will read hibernate.cfg.xml and prepare hibernate for use
         SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
          session =sessionFactory.openSession();
            //Create new instance of Contact and set values in it by reading them from form object
             System.out.println("Inserting Record");
             Transaction tx = session.beginTransaction();
             Contact contact = new Contact();
             contact.setFirstName("Arun");
             contact.setLastName("Jain");
             contact.setEmail("akj_lh@yahoo.co.in");
             session.save(contact);
             tx.commit();
            System.out.println("Done");
      }catch(Exception e){
         System.out.println(e.getMessage());
      }finally{
         // Actual contact insertion will happen at this step
      //   session.flush();
      //   session.close();

         }
      
   }
}


And get the following response

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder
at org.slf4j.LoggerFactory.getSingleton(LoggerFactory.java:223)
at org.slf4j.LoggerFactory.bind(LoggerFactory.java:120)
at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:111)
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:269)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:242)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:255)
at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:152)
at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:24)
Caused by: java.lang.ClassNotFoundException: org.slf4j.impl.StaticLoggerBinder
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
... 8 more

Any ideas?
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Rode
 Post subject: Re: Session not closing properly?
PostPosted: Mon Mar 01, 2010 1:04 pm 
Newbie

Joined: Thu Feb 25, 2010 11:09 am
Posts: 7
OK got it to work!
(added a file called slf4j-nop-1.5.8.jar as well)
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