<?xml version="1.0"?>

 <!DOCTYPE hibernate-mapping

 PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

 <hibernate-mapping >

    <class name="mypack.Monkey" table="MONKEYS">

       <id name="id" type="long" column="ID">

         <generator class="increment"/>

       </id>

       <property name="name" type="string" column="NAME" />

       <many-to-one

         name="team"

         column="TEAM_ID"

         class="mypack.Team"

       />

       <joined-subclass name="mypack.JMonkey" table="JMONKEYS" >

          <key column="MONKEY_ID" />

          <property name="color" column="COLOR" type="string" />

       </joined-subclass>

       <joined-subclass name="mypack.CMonkey"  table="CMONKEYS" >

          <key column="MONKEY_ID" />

          <property name="length" column="LENGTH" type="double" />

       </joined-subclass>

     </class>

 </hibernate-mapping>

 <?xml version="1.0"?>

 <!DOCTYPE hibernate-mapping

 PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

 <hibernate-mapping >

   <class name="mypack.Team" table="TEAMS" >

     <id name="id" type="long" column="ID">

       <generator class="increment"/>

     </id>

     <property name="name" type="string"  column="NAME" />

     <set

         name="monkeys"

         inverse="true"

     >

         <key column="TEAM_ID" />

         <one-to-many class="mypack.Monkey" />

      </set>   

   </class>

 </hibernate-mapping>

 package mypack;

 abstract public class Monkey {

     private Long id;

     private String name;

     private Team team;

     /** full constructor */

     public Monkey(String name,Team team) {

         this.name = name;

         this.team = team;

     }

     /** default constructor */

     public Monkey() {

     }

     public Long getId() {

         return this.id;

     }

     public void setId(Long id) {

         this.id = id;

     }

     public String getName() {

         return this.name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public Team getTeam() {

         return this.team;

     }

     public void setTeam(Team team) {

         this.team = team;

     }

 }

 package mypack;

 import java.io.Serializable;

 public class CMonkey extends Monkey {

     private double length;

     /** full constructor */

     public CMonkey(String name, double length,Team team) {

         super(name,team);

         this.length=length;

     }

     /** default constructor */

     public CMonkey() {

     }

    public double getLength() {

         return this.length;

     }

     public void setLength(double length) {

         this.length = length;

     }

 }

 package mypack;

 public class JMonkey extends Monkey{

     private String color;

     /** full constructor */

     public JMonkey(String name, String color,Team team) {

         super(name,team);

         this.color=color;

     }

     /** default constructor */

     public JMonkey() {

     }

     public String getColor() {

         return this.color;

     }

     public void setColor(String color) {

         this.color = color;

     }

 }

 package mypack;

 import java.util.Set;

 import java.util.HashSet;

 public class Team {

     private Long id;

     private String name;

     private Set monkeys=new HashSet();

     /** full constructor */

     public Team(String name, Set monkeys) {

         this.name = name;

         this.monkeys = monkeys;

     }

     /** default constructor */

     public Team() {

     }

     /** minimal constructor */

     public Team(Set monkeys) {

         this.monkeys = monkeys;

     }

     public Long getId() {

         return this.id;

     }

     public void setId(Long id) {

         this.id = id;

     }

     public String getName() {

         return this.name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public Set getMonkeys() {

         return this.monkeys;

     }

     public void setMonkeys(Set monkeys) {

         this.monkeys = monkeys;

     }

 }

 package mypack;

 import org.hibernate.*;

 import org.hibernate.cfg.Configuration;

 import java.util.*;

 import java.sql.*;

 public class BusinessService{

   public static SessionFactory sessionFactory;

   static{

      try{

        Configuration config = new Configuration().configure();

        sessionFactory = config.buildSessionFactory();

     }catch(RuntimeException e){e.printStackTrace();throw e;}

   }

   public void saveMonkey(Monkey monkey){

       Session session = sessionFactory.openSession();

       Transaction tx = null;

       List results=new ArrayList();

       try {

        tx = session.beginTransaction();

        session.save(monkey);

        tx.commit();

     }catch (RuntimeException e) {

       if (tx != null) {

         tx.rollback();

       }

       throw e;

     } finally {

       session.close();

     }

   }

   public List findAllJMonkeys(){

       Session session = sessionFactory.openSession();

       Transaction tx = null;

       try {

        tx = session.beginTransaction();

        List results=session.createQuery("from JMonkey").list();

        tx.commit();

        return results;

     }catch (RuntimeException e) {

       if (tx != null) {

         tx.rollback();

       }

       throw e;

     } finally {

       session.close();

     }

   }

   public List findAllMonkeys(){

       Session session = sessionFactory.openSession();

       Transaction tx = null;

       try {

        tx = session.beginTransaction();

        List results=session.createQuery("from Monkey").list();

        tx.commit();

        return results;

      }catch (RuntimeException e) {

       if (tx != null) {

         tx.rollback();

       }

       throw e;

     } finally {

       session.close();

     }

   }

   public Team loadTeam(long id){

       Session session = sessionFactory.openSession();

       Transaction tx = null;

       try {

        tx = session.beginTransaction();

        Team team=(Team)session.get(Team.class,new Long(id));

        Hibernate.initialize(team.getMonkeys());

        tx.commit();

        return team;

     }catch (RuntimeException e) {

       if (tx != null) {

         tx.rollback();

       }

       throw e;

     } finally {

       session.close();

     }

   }

    public void test(){

       List jMonkeys=findAllJMonkeys();

       printAllMonkeys(jMonkeys.iterator());

       List monkeys=findAllMonkeys();

       printAllMonkeys(monkeys.iterator());

       Team team=loadTeam(1);

       printAllMonkeys(team.getMonkeys().iterator());

       Monkey monkey=new JMonkey("Mary","yellow",team);

       saveMonkey(monkey);

   }

   private void printAllMonkeys(Iterator it){

      while(it.hasNext()){

         Monkey m=(Monkey)it.next();

         if(m instanceof JMonkey)

           System.out.println(((JMonkey)m).getColor());

         else

           System.out.println(((CMonkey)m).getLength());

       }

   }

   public static void main(String args[]) {

     new BusinessService().test();

     sessionFactory.close();

   }

 }

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

 <!DOCTYPE hibernate-configuration

  PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"

  "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

 <hibernate-configuration>

     <session-factory>

         <property name="dialect">

             org.hibernate.dialect.MySQLDialect

         </property>

         <property name="connection.driver_class">

             com.mysql.jdbc.Driver

         </property>

         <property name="connection.url">

             jdbc:mysql://localhost:3306/sampledb

         </property>

         <property name="connection.username">

             root

         </property>

         <property name="connection.password">

             1234

         </property>

         <property name="show_sql">true</property>

         <mapping resource="mypack/Team.hbm.xml" />

         <mapping resource="mypack/Monkey.hbm.xml" />

     </session-factory>

 </hibernate-configuration>

 drop database if exists SAMPLEDB;

 create database SAMPLEDB;

 use SAMPLEDB;

 create table TEAMS (

    ID bigint not null,

    NAME varchar(15),

    primary key (ID)

 );

 create table MONKEYS (

    ID bigint not null,

    NAME varchar(15),

    TEAM_ID bigint,

    primary key (ID)

 );

 create table JMONKEYS (

    MONKEY_ID bigint not null,

    COLOR varchar(15),

    primary key (MONKEY_ID)

 );

 create table CMONKEYS (

    MONKEY_ID bigint not null,

    LENGTH double precision,

    primary key (MONKEY_ID)

 );

 alter table MONKEYS add index IDX_TEAM(TEAM_ID), add constraint FK_TEAM foreign key (TEAM_ID) references TEAMS (ID);

 alter table JMONKEYS add index IDX_MONKEY1(MONKEY_ID), add constraint FK_MONKEY1 foreign key (MONKEY_ID) references MONKEYS (ID);

 alter table CMONKEYS add index IDX_MONKEY2(MONKEY_ID), add constraint FK_MONKEY2 foreign key (MONKEY_ID) references MONKEYS (ID);

 insert into TEAMS(ID,NAME) values(1,'NBA');

 insert into MONKEYS(ID,NAME,TEAM_ID) values(1,'Tom',1);

 insert into JMONKEYS(MONKEY_ID,COLOR) values(1,'yellow');

 insert into MONKEYS(ID,NAME,TEAM_ID) values(2,'Mike',1);

 insert into JMONKEYS(MONKEY_ID,COLOR) values(2,'orange');

 insert into MONKEYS(ID,NAME,TEAM_ID) values(3,'Jack',1);

 insert into CMONKEYS(MONKEY_ID,LENGTH) values(3,1.2);

 insert into MONKEYS(ID,NAME,TEAM_ID) values(4,'Linda',1);

 insert into CMONKEYS(MONKEY_ID,LENGTH) values(4,2.0);