Hibernate:Nullpointer exception

[Bk Jacky]

HI,
I am new for hibernate, while executing main method I am getting nullpointer exception. please some body guide me whats the wrong in my code.

package roseindia.tutorial.hibernate;

import java.io.File;

import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
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
System.out.println("getEventInfo");
File file = new File("D:\\bea\\user_projects\\w4WP_workspaces\\Untitled\\Hyber\\hibernate.cfg.xml"); //yu see I have used full path
// This is my first run I will chenge to relative path later
System.out.println(file.exists());

SessionFactory sessionFactory = new Configuration().configure(file).buildSessionFactory();
if(sessionFactory == null) {
System.out.println("NULL"); //Testing it
}
else {
System.out.println("NOT NULL");
}

//SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
System.out.println("Sessiong Factory After");
session =sessionFactory.openSession();
//Create new instance of Contact and set values in it by reading them from form object
System.out.println("Inserting Record");
Contact contact = new Contact();
contact.setId(3);
contact.setFirstName("Deepak");
contact.setLastName("Kumar");
contact.setEmail("[e-mail]");
session.save(contact);
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();

}

}

}

Error is

getEventInfo
true
Exception in thread "Main Thread" java.lang.NullPointerException
at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:52)

[Cameron Wallace McKenzie]

Break this into separate method calls:

SessionFactory sessionFactory = new Configuration().configure(file).buildSessionFactory();

Put your println after each one and see which line is kicking out null. Maybe even a try catch.

Here's some code from a tutorial of mine that shows you how to get started with Hiberante and Hibernate Annotations:

  
AnnotationConfiguration config = 
             new AnnotationConfiguration();
config.addAnnotatedClass(User.class);
config.configure();
// new SchemaExport(config).create(true, true);
/*The SessionFactory is obtained 
through the config object*/
SessionFactory factory = 
           config.buildSessionFactory();
/* The User instance is still transient 
and not associated with any Hibernate Session.*/
User u = new User();
u.setPassword("abc123");  

A Simple Tutorial on How to Add Database Records with Hibernate and JPA Annotations

Notice how I use 3 lines of code to get the the SessionFactory. That's probably a good way to start off.

Keep us appraised of your progress.

-Cameron McKenzie

[Bk Jacky]

Hi Cameron,

I break down the code as per your suggestion and found out that following line is not excuting...

SessionFactory sessionFactory =config.buildSessionFactory();

This line is throwing NULLPointer exception. hibernate.cf.xml and contct.hbm.xml files are in class path... i don't know what's going wrong...

[Mark Spritzler]

"hibernate.cf.xml"

Where's the "g"? Is it missing form your keyboard?

as in

hibernate.cfg.xml

And do you not like vowels?

"contct.hbm.xml"

is that supposed to be "contact"

Anyway, can you also post the exact stack trace that you are getting, it will show us a lot more.

Thanks

Mark

[Mark Spritzler]

Actually also looking at your code I see you have this

  
File file = new File("D:\\bea\\user_projects\\w4WP_workspaces\\Untitled\\Hyber\\hibernate.cfg.xml"); //yu see I have used full path
// This is my first run I will chenge to relative path later
System.out.println(file.exists());
 
SessionFactory sessionFactory = new Configuration().configure(file).buildSessionFactory();  

If you have your hibernate.cfg.xml in the root of your classpath, then you do not need to create a File object and use that method version to create your SessionFactory.

You can simple do

SessionFactory sessionFactory = new Configuration().configure.buildSessionFactory();

Here is the most common way people do. The make a HibernateUtil class like

  
package util;
 
import org.hibernate.*;
import org.hibernate.cfg.*;
 
public class HibernateUtil {
 
    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 static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
 
}
 
  

I stole that completely from the hibernate.org documentation page.

Mark

[Cameron Wallace McKenzie]

Mark,

Vowels cost $500.

Have you never seen Wheel of Fortune?

-Cameron McKenzie

[labi laba]

I am also having the same problem, null pointer exception. Please help me out. I have hibernate.cfg.xml in /src directory so that its automatically included to build path.

[Mark Spritzler]

Originally posted by labi laba:
I am also having the same problem, null pointer exception. Please help me out. I have hibernate.cfg.xml in /src directory so that its automatically included to build path.

Can you create a new thread for your issue.

Include your pathing, classpath, and your hibernate.cfg.xml and how you package it all up

Thanks

Mark

[labi laba]

hi mark,
i have created a new thread here
http://www.coderanch.com/t/218498/ORM/java/Hibernate-configuration

any ideas/suggestions?thanks