关于hibernate3.3.1的annotations配置问题?

先帖代码吧
HibernateUtils.java
[code="java"]
package com;
import org.apache.log4j.Logger;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.Session;

public class HibernateUtils {

private static final Logger logger = Logger.getLogger(HibernateUtils.class);

private static final SessionFactory sessionFactory;

static {
    try 
    {
        //System.out.println(new AnnotationConfiguration().configure().buildSessionFactory());
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        //sessionFactory = new AnnotationConfiguration().configure("/hibernate.cfg.xml").buildSessionFactory(); 

    } catch (Exception e) {
        logger.error(e.getMessage());
        throw new ExceptionInInitializerError(e);
    }
}

public static Session getSession() {
    return sessionFactory.openSession();
}

}
[/code]
User.java
[code="java"]
package com;
import javax.persistence.*;

@Entity
@Table(name="user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String name;
private String password;
private String email;
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}

[/code]
MainClass.java
[code="java"]
package com;

import org.hibernate.Session;
import org.hibernate.Transaction;

public class MainClass {

/**
 * @param args
 */
public static void main(String[] args) {
    User user = new User();
    user.setName("andy");
    user.setPassword("123456");
    user.setEmail("andy@123.com");

    Session session = HibernateUtils.getSession();
    Transaction tx = session.beginTransaction();
    session.saveOrUpdate(user);
    tx.commit();
}

}
[/code]
执行的时候出现
Exception in thread "main" java.lang.NoClassDefFoundError: org/hibernate/annotations/common/reflection/ReflectionManager
at com.HibernateUtils.(HibernateUtils.java:17)
at com.MainClass.main(MainClass.java:17)
错误,不知道怎么解决.第一个demo希望支持下

差一个jar包, 将hibernate-commons-annotations.jar加入到classpath中