postgresql - Error in Hibernate Program

Question

I just started working on Hibernate but faced errors with the first program itself. Please help me identify the error. Here is the code. I am using Hibernate 4.2.7 and postgreSQL 9.3

hibernate.cfg.xml

 <?xml version='1.0' encoding='utf-8'?>

 <hibernate-configuration
    xmlns="http://www.hibernate.org/xsd/hibernate-configuration"
    xsi:schemaLocation="http://www.hibernate.org/xsd/hibernate-configuration hibernate-         configuration-4.0.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<session-factory>
<!-- Database connection settings -->
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/hibernatedb</property>
<property name="hibernate.connection.username">postgres</property>
<property name="hibernate.connection.password">password</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache  -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>
<mapping class="org.hibernate.tutorial.dto.UserDetails"/>

UserDetails.java

 package org.hibernate.tutorial.dto;

 import javax.persistence.Entity;
 import javax.persistence.Id;

 @Entity
 public class UserDetails { 
@Id
private int userId;
private String userName;

public int getUserId() {
    return userId;
}
public void setUserId(int userId) {
    this.userId = userId;
}
public String getUserName() {
    return userName;
}
public void setUserName(String userName) {
    this.userName = userName;
} 

}

HibernateTest.java

package org.hibernate.test;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.tutorial.dto.UserDetails;

public class HibernateTest {

/**
 * @param args
 */
public static void main(String[] args) {
    UserDetails mUser = new UserDetails();
    mUser.setUserId(1);
    mUser.setUserName("freak");

    try {
        SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save(mUser);
        session.getTransaction().commit();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

} 

And the error I am facing is....

org.hibernate.MappingException: invalid configuration at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2095) at org.hibernate.cfg.Configuration.configure(Configuration.java:2012) at org.hibernate.cfg.Configuration.configure(Configuration.java:1991) at org.hibernate.test.HibernateTest.main(HibernateTest.java:19) Caused by: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 25; Document is invalid: no grammar found.

UPDATE: It worked after making some modifications. I changed the xml content to this.

hibernate.cfg.xml

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

<session-factory>

    <!-- Database connection settings -->
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/hibernatedb</property>
<property name="hibernate.connection.username">postgres</property>
<property name="hibernate.connection.password">password</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache  -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>
<mapping class="org.hibernate.tutorial.dto.UserDetails"/>

Answer 1

It worked after changing the header in configuration file to this

hibernate.cfg.xml

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