session.flush(); gives null

[sameera liyanage]

this is my hibernate.cfg.xml code

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
		"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
		"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        
        
     <property name="hibernate.connection.driver_class">
	com.mysql.jdbc.Driver
	</property>
	
     <property name="hibernate.connection.url">
	jdbc:mysql://localhost/hibernatetutorial
	</property>
      <property name="hibernate.connection.username">root</property>
      <property name="hibernate.connection.password"></property>
      <property name="hibernate.connection.pool_size">10</property>
      <property name="show_sql">true</property>
      <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
      <property name="hibernate.hbm2ddl.auto">update</property>
      <!-- Mapping files -->
      <mapping resource="contact.hbm.xml"/>
        
        
    </session-factory>
</hibernate-configuration>

this is my Contact,java code

package roseindia.tutorial.hibernate;

public class Contact {
	  private String firstName;
	  private String lastName;
	  private String email;
	  private long id;

	  
	  public String getEmail() {
	    return email;
	  }

	 
	  public String getFirstName() {
	    return firstName;
	  }

	  
	  public String getLastName() {
	    return lastName;
	  }

	 
	  public void setEmail(String string) {
	    email = string;
	  }

	  
	  public void setFirstName(String string) {
	    firstName = string;
	  }

	
	  public void setLastName(String string) {
	    lastName = string;
	  }

	
	  public long getId() {
	    return id;
	  }

	 
	  public void setId(long l) {
	    id = l;
	  }

	

}

this is my contact.hbm.xml code

<?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="roseindia.tutorial.hibernate.Contact" table="CONTACT">
   <id name="id" type="long" column="ID" >
   <generator class="assigned"/>
  </id>

  <property name="firstName">
     <column name="FIRSTNAME" />
  </property>
  <property name="lastName">
    <column name="LASTNAME"/>
  </property>
  <property name="email">
    <column name="EMAIL"/>
  </property>
 </class>
</hibernate-mapping>

this is my test class

package roseindia.tutorial.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{
     
      SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
       session =sessionFactory.openSession();
       
         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();

      }
    
  }
} 

in the test class session.flush(); gives null
here is the error

Exception in thread "main" java.lang.NullPointerException
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:36)

[Rahul Babbar]

Hi,

Quite a few things..

1. Create a Transaction and save your entity inside that transaction.
2. Check to see if you got any exception while building the session factory...i.e. any exception on the console before this error.

it is possible that the creation of your sessionFactory and session failed(ie and error in line 21), and your session is null, hence giving a null pointer...

[sameera liyanage]

but if i comment the flush and close it gives this

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
	at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:110)
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:21)

[sameera liyanage]

anyway how to save this in a transaction?

[sameera liyanage]

i only add the hibernate3.jar and mysql-connector-java-3.1.6-bin.jar.ithink it is enough.

[Rahul Babbar]

aruna sameera wrote:but if i comment the flush and close it gives this

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
	at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:110)
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:21)

Add the commons-logging.jar to your application classpath.

You need to save the entities in a Transaction like

Transaction tx = session.beginTransaction();
// populate and save your entity.
tx.commit();
// if some exception occurs, check if the transaction is Active, if it is, do a tx.rollback();


Please do a 'google' for some hibernate tutorials, go through them for proper understanding.

[sameera liyanage]

i change my test class to this

package roseindia.tutorial.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{
     
      SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
       session =sessionFactory.openSession();
       
         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){
    	e.printStackTrace();
      System.out.println(e.getMessage());
    }finally{
      // Actual contact insertion will happen at this step    	
      session.flush();
     session.close();

      }
    
  }
} 

then error is

May 20, 2009 6:37:00 PM org.hibernate.cfg.Environment <clinit>
INFO: Hibernate 3.0rc1
May 20, 2009 6:37:00 PM org.hibernate.cfg.Environment <clinit>
INFO: hibernate.properties not found
May 20, 2009 6:37:00 PM org.hibernate.cfg.Environment <clinit>
INFO: using CGLIB reflection optimizer
May 20, 2009 6:37:00 PM org.hibernate.cfg.Environment <clinit>
INFO: using JDK 1.4 java.sql.Timestamp handling
May 20, 2009 6:37:00 PM org.hibernate.cfg.Configuration configure
INFO: configuring from resource: /hibernate.cfg.xml
May 20, 2009 6:37:00 PM org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: Configuration resource: /hibernate.cfg.xml
May 20, 2009 6:37:00 PM org.hibernate.cfg.Configuration getConfigurationInputStream
WARNING: /hibernate.cfg.xml not found
org.hibernate.HibernateException: /hibernate.cfg.xml not found
	at org.hibernate.cfg.Configuration.getConfigurationInputStream(Configuration.java:1205)
	at org.hibernate.cfg.Configuration.configure(Configuration.java:1229)
	at org.hibernate.cfg.Configuration.configure(Configuration.java:1216)
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:21)
Exception in thread "main" java.lang.NullPointerException
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:37)/hibernate.cfg.xml not found

[Rahul Babbar]

aruna sameera wrote:i change my test class to this

WARNING: /hibernate.cfg.xml not found
org.hibernate.HibernateException: /hibernate.cfg.xml not found
	at org.hibernate.cfg.Configuration.getConfigurationInputStream(Configuration.java:1205)
	at org.hibernate.cfg.Configuration.configure(Configuration.java:1229)
	at org.hibernate.cfg.Configuration.configure(Configuration.java:1216)
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:21)
Exception in thread "main" java.lang.NullPointerException
	at roseindia.tutorial.hibernate.FirstExample.main(FirstExample.java:37)/hibernate.cfg.xml not found

clearly it says that your hibernate.cfg.xml file is not found. Do you have such a file. If yes, where is it?
Please go through some simple hibernate tutorial on the net..

[Cameron Wallace McKenzie]

Indeed, it looks like it's the location of the hibernate.cfg.xml file that's at issue.

People often put it next to a HibernateUtil class or in a package folder. The root of your source folder should be good enough.

Here's a little tutorial on setting up Hibernate that might be helpful. Just get something simple started and working, and progress from there.

Getting Started with Hibernate


-Cameron McKenzie