Problem with the sample hibernate program

[Keerthi Kumar]

Dear all,

Earlier had worked with hibernate framework with oracl and mysql database. Now I am trying the same with the Postgres database. But I am not able to save the data. Please find my files below:

hibernate config xml file:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
	  <property name="hibernate.connection.driver_class">org.postgresql.Driver</property> 
	  <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/TestDb/keerthi_dev</property> 
      <property name="hibernate.connection.username">postgres</property>
      <property name="hibernate.connection.password">postgres</property>
      <property name="hibernate.connection.pool_size">10</property>
      <property name="show_sql">true</property>
      <property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
      <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
      <property name="hibernate.hbm2ddl.auto">update</property>
	
		<mapping resource="Student.hbm.xml" />
</session-factory>
</hibernate-configuration>

student.hbm.xml file :

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
  <class name="com.Hibernate.Demo.Student" table="student">
     
  	<id name="regno" type="java.lang.Integer" column="regno" >
		<generator class="increment"/>	</id>
      <property name="name" type="java.lang.String" column="name" />
  	  <property name="course" type="java.lang.String" column="course" />
      <property name="city" type="java.lang.String" column="city"/>
  
 </class>
</hibernate-mapping>

SaveDemo.java

package com.Hibernate.Demo;

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

public class SaveDemo 
{
	
	public static void main(String[] args) 
	{
		Session session = null;
		Transaction trans = null;
		SessionFactory sessFact = null;
		try
		{
			System.out.println("Inside the try block");
			Configuration config = new Configuration();
			sessFact = config.configure().buildSessionFactory();
			session = sessFact.openSession();
			System.out.println("Before inserting records into STUDENT table");			
			Student stu = new Student();			
			//stu.setRegno(3014);
			stu.setName("Keerthi Kumar");
			stu.setCourse("MCA");
			stu.setCity("Bangalore");			
			System.out.println("Name : "+stu.getName());
			System.out.println("Course : "+stu.getCourse());
			System.out.println("City : "+stu.getCity());
			trans = session.beginTransaction();
			session.save(stu);
			System.out.println("After inserting records into STUDENT table");	
			
		}
		catch(HibernateException he)
		{
			he.printStackTrace();
		}
		finally
		{
			session.close();
			System.out.println("Records inserted successfully !!"); 
		}
	}
}

[Keerthi Kumar]

Dear all,

I am able to get a connection to the postgres database as well. But when I execute the main class (SaveDemo.java), the values are not being inserted into the db. Also I am not getting any errors or exception for the same.

Request you all to help me out in this.

[Sridhar Santhanakrishnan]

You have opened a transaction. However, there is no transaction commit or close done in your code. Have you posted the complete code?

[Keerthi Kumar]

Hi Sridhar,

I had added that trans.commit() in the finally block. But it was throwing some error Hence i removed that line. Please help me out.

[Prasad Krishnegowda]

Without committing the data will not be inserted.. Can you tell us what error you were getting when you added that
trans.commit ()

[vijin das]

put trans.commit() in the try block itself after session.save() .... try this code ..and test

 public static void main(String[] args) 
{ 
Session session = null; 
Transaction trans = null; 
SessionFactory sessFact = null; 
try { 
System.out.println("Inside the try block"); 
Configuration config = new Configuration(); 
sessFact = config.configure().buildSessionFactory(); 
session = sessFact.openSession();
 System.out.println("Before inserting records into STUDENT table");
 Student stu = new Student(); //stu.setRegno(3014); 
stu.setName("Keerthi Kumar"); stu.setCourse("MCA");
 stu.setCity("Bangalore"); 
System.out.println("Name : "+stu.getName());
 System.out.println("Course : "+stu.getCourse()); 
System.out.println("City : "+stu.getCity());
 trans = session.beginTransaction(); 
session.save(stu);
 trans.commit();

 System.out.println("After inserting records into STUDENT table"); 
} 
 catch (RuntimeException re) {
if (trans != null && trans.isActive()) {
try {
// Second try catch as the rollback could fail as well
trans.rollback();
} catch (HibernateException he) {
System.out.println("Error rolling back transaction");
}
// throw again the first exception
throw re;
}
finally { 
session.close(); 
System.out.println("Records inserted successfully !!");
 } 
}
   

[Paul Sturrock]

...though of course, if calling commit() in the finally block is " throwing some error " moving it to the catch block is unlikely to fix this. What is the error?

[Keerthi Kumar]

Hi,

Thanks a lot It is working fine now

[Keerthi Kumar]

Dear All,

Once again stuck up with a small issue.But I am not able to figure it out. In the previously mentioned code snippet, when the control invokes the below line of code, the control is directly moving to the session.close() method of the finally block :

sessFact = new Configuration().configure().buildSessionFactory();

Request to help me to solve this issue.

[Christian Dillinger]

When it's moving to the finally-bock without printing some of the System.outs you have in there, there should be a stacktrace which might help us a little bit...

[Keerthi Kumar]

Dear,

After coming to session.close() of the finally block, it is just printing null pointer exception at the line of session.close()

[Keerthi Kumar]

Dear all,

Below is the error I am getting while trying to execute the above give program:

Inside the try block
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.NullPointerException
	at com.Hibernate.Demo.SaveDemo.main(SaveDemo.java:53)
ERROR: JDWP Unable to get JNI 1.2 environment, jvm->GetEnv() return code = -2
JDWP exit error AGENT_ERROR_NO_JNI_ENV(183):  [../../../src/share/back/util.c:820]

Please help me out to resolve this issue.

[Christian Dillinger]

As you didn't post the code of your program, we cannot know whats in line 53. I think it is "session.close()" which is inside a finally block. Something went wrong opening the connection, a runtime exception occured which you re-throw. After that the finally-block is being processed where the NPE occurs because the session is null. But as you didn't post the stacktrace of the exception we cannot know, what happened exactly. There MUST be a stacktrace. You could print it right before re-throwing the RuntimeException.

[Keerthi Kumar]

Dear all,

I just changed the asm.jar and cglib.jar to the latest versions. It worked fine. Thanks to you all for your valuable support and guidance.