hi

i am trying to save a object in to Mysql database. its throwing Null pointer exception. Please help me....

MySql-Jdbc-driver : mysql-connector-java-5.0.8
MySql databse version: MySql 5.0
Hibernate version: hibernate-distribution-3.5.0

Error:
Exception in thread "Main Thread" java.lang.NullPointerException
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:649)
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:587)
at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:4068)
at java.lang.String.valueOf(String.java:2826)
at java.lang.StringBuffer.append(StringBuffer.java:219)
at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
at com.mysql.jdbc.Connection.registerStatement(Connection.java:5005)
at com.mysql.jdbc.Statement.<init>(Statement.java:270)
at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:500)
at com.mysql.jdbc.Connection.clientPrepareStatement(Connection.java:2187)
at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4829)
at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4734)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:534)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:116)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:109)
at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:244)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2395)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2858)
at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:268)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:260)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:179)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1206)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:344)
at $Proxy0.flush(Unknown Source)
at com.sample.test.SampleHibernate.main(SampleHibernate.java:26)


Main Program:


package com.sample.test;

import java.util.Calendar;
import java.util.Date;

import org.hibernate.Session;

import com.sample.model.Person;

public class SampleHibernate {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Session session = SampleUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
Person pers = new Person();
pers.setId(new Long(1));
pers.setFirstName("sandeep");
pers.setLastName("velaga");
Date date=Calendar.getInstance().getTime();
pers.setDateOfBirth(date);
session.save(pers);
session.flush();
}

}


Hibernate.cfg.xml:

<?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">org.gjt.mm.mysql.Driver</property>
<property name="hibernate.connection.password">1484</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/sandeep</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="hibernate.current_session_context_class">org.hibernate.context.ThreadLocalSessionContext</property>
<property name="show_sql">true</property>
<!-- mapping files -->
<mapping resource="Person.hbm.xml"/>
</session-factory>
</hibernate-configuration>




Hibernate mapping file(hbm.xml):


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 4 May, 2011 3:14:15 PM by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
<class name="com.sample.model.Person" table="PERSON">
<id name="id" type="java.lang.Long">
<column name="PERSON_ID" />
<generator class="assigned" />
</id>
<property name="firstName" type="java.lang.String">
<column name="FIRST_NAME" />
</property>
<property name="LastName" type="java.lang.String">
<column name="LAST_NAME" />
</property>
<property name="dateOfBirth" type="java.util.Date">
<column name="DATE_OF_BIRTH" />
</property>
</class>
</hibernate-mapping>

Please help me to resolve this issue.