I tried to see all the questions on this topic but none of them helped me. And I really want to understand what is going on with my code.

I have a standalone application which uses spring and Hibernate as JPA and I am trying to run the test using a single main Class

My main class

package edu.acct.tsegay.common;

import edu.acct.tsegay.model.User;
import edu.acct.tsegay.business.IUserBusinessObject;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App {
    public static void main(String[] args) {
        try {
            ApplicationContext context = new ClassPathXmlApplicationContext(
                    "Spring3AndHibernate-servlet.xml");
            IUserBusinessObject userBusinessObject = (IUserBusinessObject) context
                    .getBean("userBusiness");

            User user = (User) context.getBean("user1");
            user.setPassword("pass");
            user.setUsername("tsegay");
            System.out.println(user.getPassword());

            userBusinessObject.delete(user);

            User user2 = new User();
            user2.setUsername("habest");
            user2.setPassword("pass1");
            System.out.println(user2.getPassword());
            /*
             * userBusinessObject.save(user2);
             * 
             * User user3 = userBusinessObject.searchUserbyId("tsegay");
             * System.out.println("Search Result: " + user3.getUsername());
             */
            System.out.println("Success");
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

my application context is:

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <!-- data source -->
    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/test" />
        <property name="username" value="test" />
        <property name="password" value="password" />
    </bean>

    <!-- session factory -->
    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">

        <property name="dataSource">
            <ref bean="dataSource" />

        </property>

        <property name="hibernateProperties">

            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
            </props>
        </property>



    </bean>

    <!-- exposed person business object -->
    <bean id="userBusiness" class="edu.acct.tsegay.business.UserBusinessObject">
        <property name="userDao" ref="userDao" />

    </bean>
    <bean id="user1" class="edu.acct.tsegay.model.User">
        <property name="username" value="tse" />
        <property name="password" value="pass" />
    </bean>


    <!-- Data Access Object -->
    <bean id="userDao" class="edu.acct.tsegay.dao.UserDao">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>


</beans>

My User Model is:

package edu.acct.tsegay.model;

import java.io.Serializable;

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

import org.hibernate.annotations.NaturalId;

@Entity
public class User implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private String username;
    private String password;
    private Integer VERSION;

    @Version
    public Integer getVERSION() {
        return VERSION;
    }

    public void setVERSION(Integer vERSION) {
        VERSION = vERSION;
    }
    @NaturalId
    public String getUsername() {
        return username;
    }


    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

My DAO is:

package edu.acct.tsegay.dao;

import edu.acct.tsegay.model.User;

import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.hibernate3.HibernateTemplate;

import org.springframework.stereotype.Repository;

@Repository
public class UserDao implements IUserDao {
    private SessionFactory sessionFactory;

    private HibernateTemplate hibernateTemplate;

    public SessionFactory getSessionFactory() {
        return sessionFactory;
    }
    @Autowired
    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
        this.hibernateTemplate = new HibernateTemplate(sessionFactory);
    }

    public void save(User user) {
        // TODO Auto-generated method stub
        // getHibernateTemplate().save(user);
        this.hibernateTemplate.save(user);
    }

    public void delete(User user) {
        // TODO Auto-generated method stub
        this.hibernateTemplate.delete(user);
    }

    public User searchUserbyId(String username) {
        // TODO Auto-generated method stub
        return this.hibernateTemplate.get(User.class, username);
    }

}

And this my stacktrace error when i run the program:

pass
org.springframework.orm.hibernate3.HibernateSystemException: Unknown entity: edu.acct.tsegay.model.User; nested exception is org.hibernate.MappingException: Unknown entity: edu.acct.tsegay.model.User
    at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:679)
    at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
    at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:411)
    at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
    at org.springframework.orm.hibernate3.HibernateTemplate.delete(HibernateTemplate.java:837)
    at org.springframework.orm.hibernate3.HibernateTemplate.delete(HibernateTemplate.java:833)
    at edu.acct.tsegay.dao.UserDao.delete(UserDao.java:34)
    at edu.acct.tsegay.business.UserBusinessObject.delete(UserBusinessObject.java:30)
    at edu.acct.tsegay.common.App.main(App.java:23)
Caused by: org.hibernate.MappingException: Unknown entity: edu.acct.tsegay.model.User
    at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:580)
    at org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1365)
    at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:100)
    at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:74)
    at org.hibernate.impl.SessionImpl.fireDelete(SessionImpl.java:793)
    at org.hibernate.impl.SessionImpl.delete(SessionImpl.java:771)
    at org.springframework.orm.hibernate3.HibernateTemplate$25.doInHibernate(HibernateTemplate.java:843)
    at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406)
    ... 6 more

Please let me know if you need any more of my configuration. Any help is much appreciated..