Exception java.lang.NoClassDefFoundError

25/01/2007 22:05:19 org.hibernate.cfg.SettingsFactory buildSettings
INFO: Default entity-mode: pojo
Exception in thread "main" java.lang.NoClassDefFoundError: javax/transaction/Synchronization
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1005)
	at com.integrallis.TechConf.domain.TestaMapeamento.main(TestaMapeamento.java:20)

package com.integrallis.TechConf.domain;

import java.io.*;
import java.util.*;

import org.hibernate.cfg.*;
import org.hibernate.*;

public class TestaMapeamento {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		File configFile = new File("/home/jean/workspace/TechConf/bin/com/integrallis/TechConf/domain/hibernate.cfg.xml");
		Configuration configuration = new Configuration().configure(configFile);
		SessionFactory factory = configuration.buildSessionFactory();
		
		Session session = null;
		Transaction tx = null;
		try{
			//cria uma conferência
			Conference conference = new Conference();
			conference.setAbstractSubmissionEndDate(new Date());
			conference.setAbstractSubmissionStartDate(new Date());
			conference.setDescription("A Test Conference");
			conference.setEndDate(new Date());
			conference.setName("TestConf 2005");
			conference.setStartDate(new Date());
			//cria alguns tópicos
			Track jseTrack = new Track();
			jseTrack.setDescription("Aprenda Java para Desktop");
			jseTrack.setSubtitle("Java Standard Edition");
			jseTrack.setTitle("JSE");
			
			Track jeeTrack = new Track();
			jeeTrack.setDescription("Aprenda Java para Empresas");
			jeeTrack.setSubtitle("Java Enterprise Edition");
			jeeTrack.setTitle("JEE");
			
			Track jmeTrack = new Track();
			jmeTrack.setDescription("Aprenda Java para Celulares");
			jmeTrack.setSubtitle("Java Micro Edition");
			jmeTrack.setTitle("JME");
			
			//adiciona os tópicos à conferência :) duvido!
			conference.addTrack(jseTrack);
			conference.addTrack(jeeTrack);
			conference.addTrack(jmeTrack);
			
			//persiste a conferência :P aí o bixo pega
			session = factory.openSession();
			tx = session.beginTransaction();
			session.persist(conference);
			tx.commit();
			
		}catch (Exception e){
			if (tx != null){
				tx.rollback();
			}
		}finally{
			session.close();
		}
		
	}

}

<?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 name="hibernate.connection.url">
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">forumguj</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost/TECHCONF</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
		<!--Mapeamentos -->
		<mapping resource="com/integrallis/TechConf/domain/Address.hbm.xml"/>
		<mapping resource="com/integrallis/TechConf/domain/Conference.hbm.xml"/>
		<mapping resource="com/integrallis/TechConf/domain/Track.hbm.xml"/>
		<mapping resource="com/integrallis/TechConf/domain/Venue.hbm.xml"/>
    </session-factory>
</hibernate-configuration>