public class Main {
   public static void main(String[] args) throws Exception {
      Data usersData = new Data();
      usersData.executeExport("C:\\Users.xml");
   }
}

public class Data {
   Session session;
   Document document;
   Transaction transaction;
   public Data() {
      session = SessionFactory.currentSession();
      transaction = session.beginTransaction();
   }
   public void executeExport(String fileName) {
      try {
         document = getData();
         XMLWriter writer = new XMLWriter(new FileWriter(fileName), OutputFormat.createPrettyPrint());
         writer.write(document);
         writer.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
   private Document getData() {
      Document doc = DocumentHelper.createDocument();
      Element users = doc.addElement("users");
      Session dom4jsession = session.getSession(EntityMode.DOM4J);
      List usersList = dom4jsession.createQuery("FROM Users").list();
      Iterator i = usersList.iterator();
      for (i=usersList.iterator(); i.hasNext();) {
         Element user = (Element)i.next();
         if (user != null) {
            users.add(user);
         }
      }
      return doc;
   }
}

public class Users
    extends AbstractUsers
    implements Serializable {
   private static final long serialVersionUID = 8975703870006542838L;
    public Users() {
        super.setAddressesSet(new HashSet());
    }
    public Users(java.lang.String userName) {
        super(userName);
    }
    public void initialize(){
       Hibernate.initialize(this);
       this.getAddressesSet().size();
    }
}

public class AddressesKey
    implements Serializable
{
   private static final long serialVersionUID = -915486979622282724L;
    private volatile int hashValue = 0;
    private java.lang.String addressId;
    private Users users;
    public AddressesKey()
    {
    }
    public java.lang.String getAddressId()
    {
        return addressId;
    }
    public void setAddressId(java.lang.String addressId)
    {
        hashValue = 0;
        this.addressId = addressId;
    }
    public Users getUsers()
    {
        return users;
    }
    public void setUsers(Users users)
    {
        hashValue = 0;
        this.users = users;
    }
    public boolean equals(Object rhs)
    {
        if (rhs == null)
            return false;
        if (! (rhs instanceof AddressesKey))
            return false;
        AddressesKey that = (AddressesKey) rhs;
        if (this.getAddressId() == null || that.getAddressId() == null)
        {
            return false;
        }
        if (! this.getAddressId().equals(that.getAddressId()))
        {
            return false;
        }
        if (this.getUsers() == null || that.getUsers() == null)
        {
            return false;
        }
        if (! this.getUsers().equals(that.getUsers()))
        {
            return false;
        }
        return true;
    }
    public int hashCode()
    {
        if (this.hashValue == 0)
        {
            int result = 17;
            int addressIdValue = this.getAddressId() == null ? 0 : this.getAddressId().hashCode();
            result = result * 37 + addressIdValue;
            int usersValue = this.getUsers() == null ? 0 : this.getUsers().hashCode();
            result = result * 37 + usersValue;
            this.hashValue = result;
        }
        return this.hashValue;
    }
}

public class Addresses
    extends AbstractAddresses
    implements Serializable
{
   private static final long serialVersionUID = -1610477145149174065L;
    public Addresses()
    {
    }
    public Addresses(AddressesKey id)
    {
        super(id);
    }
}

public abstract class AbstractUsers
    implements Serializable
{
    private int hashValue = 0;
    private java.lang.String userName;
    private java.util.Set addressesSet = new HashSet();
    private java.lang.String firstName;
    private java.lang.String lastName;
    public AbstractUsers()
    {
    }
    public AbstractUsers(java.lang.String userName)
    {
        this.setUserName(userName);
    }
    public java.lang.String getUserName()
    {
        return userName;
    }
    public void setUserName(java.lang.String userName)
    {
        this.hashValue = 0;
        this.userName = userName;
    }
    public java.lang.String getFirstName()
    {
        return this.firstName;
    }
    public void setFirstName(java.lang.String firstName)
    {
        this.firstName = firstName;
    }
    public java.lang.String getLastName()
    {
        return this.lastName;
    }
    public void setLastName(java.lang.String lastName)
    {
        this.lastName = lastName;
    }
    public java.util.Set getAddressesSet()
    {
        return this.addressesSet;
    }
    public void setAddressesSet(java.util.Set addressesSet)
    {
        this.addressesSet = addressesSet;
    }
    public boolean equals(Object rhs)
    {
        if (rhs == null)
            return false;
        if (! (rhs instanceof Users))
            return false;
        Users that = (Users) rhs;
        if (this.getUserName() == null || that.getUserName() == null)
            return false;
        return (this.getUserName().equals(that.getUserName()));
    }
    public int hashCode()
    {
        if (this.hashValue == 0)
        {
            int result = 17;
            int userNameValue = this.getUserName() == null ? 0 : this.getUserName().hashCode();
            result = result * 37 + userNameValue;
            this.hashValue = result;
        }
        return this.hashValue;
    }
}

public abstract class AbstractAddresses
    implements Serializable
{
    private int hashValue = 0;
    private AddressesKey id;
    private java.lang.String street;
    private java.lang.String city;
    private java.lang.String region;
    private java.lang.String country;
    public AbstractAddresses()
    {
    }
    public AbstractAddresses(AddressesKey id)
    {
        this.setId(id);
    }
    public AddressesKey getId()
    {
        return this.id;
    }
    public void setId(AddressesKey id)
    {
        this.hashValue = 0;
        this.id = id;
    }
    public java.lang.String getStreet()
    {
        return this.street;
    }
    public void setStreet(java.lang.String street)
    {
        this.street = street;
    }
    public java.lang.String getCity()
    {
        return this.city;
    }
    public void setCity(java.lang.String city)
    {
        this.city = city;
    }
    public java.lang.String getRegion()
    {
        return this.region;
    }
    public void setRegion(java.lang.String region)
    {
        this.region = region;
    }
    public java.lang.String getCountry()
    {
        return this.country;
    }
    public void setCountry(java.lang.String country)
    {
        this.country = country;
    }
    public boolean equals(Object rhs)
    {
        if (rhs == null)
            return false;
        if (! (rhs instanceof Addresses))
            return false;
        Addresses that = (Addresses) rhs;
        if (this.getId() == null || that.getId() == null)
            return false;
        return (this.getId().equals(that.getId()));
    }
    public int hashCode()
    {
        if (this.hashValue == 0)
        {
            int result = 17;
            if (this.getId() == null)
            {
                result = super.hashCode();
            }
            else
            {
                result = this.getId().hashCode();
            }
            this.hashValue = result;
        }
        return this.hashValue;
    }
}

<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
<hibernate-mapping package="com.test.hibernate.classes">
    <class name="Users" table="users" node="user">
        <id name="userName" column="USER_NAME" type="string" node="@user_name">
            <generator class="assigned"/>
        </id>
        <property name="firstName" column="FIRST_NAME" type="string" node="first_name"/>
        <property name="lastName" column="LAST_NAME" type="string" node="last_name"/>
         <set name="addressesSet" embed-xml="true" node="addresses">
            <key column="USER_NAME"/>
            <one-to-many class="Addresses"/>
        </set>
    </class>
</hibernate-mapping>

<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
<hibernate-mapping package="com.test.hibernate.classes">
    <class name="Addresses" table="addresses">
        <composite-id name="id" class="AddressesKey">
            <key-property name="addressId" column="ADDRESS_ID" type="string"/>
            <key-many-to-one name="users" column="USER_NAME" class="Users"/>
        </composite-id>
        <property name="street" column="STREET" type="string"/>
        <property name="city" column="CITY" type="string"/>
        <property name="region" column="REGION" type="string"/>
        <property name="country" column="COUNTRY" type="string"/>
    </class>
</hibernate-mapping>

package com.test.hibernate;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
public class SessionFactory {
    private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    private static final ThreadLocal threadLocal = new ThreadLocal();
    private static final Configuration cfg = new Configuration();
    private static org.hibernate.SessionFactory sessionFactory;
    public static Session currentSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        if (session == null) {
            if (sessionFactory == null) {
                try {
                    cfg.configure(CONFIG_FILE_LOCATION);
                    sessionFactory = cfg.buildSessionFactory();
                }
                catch (Exception e) {
                    System.err.println("%%%% Error Creating SessionFactory %%%%");
                    e.printStackTrace();
                }
            }
            session = sessionFactory.openSession();
            threadLocal.set(session);
        }
        return session;
    }
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);
        if (session != null) {
            session.close();
        }
    }
    private SessionFactory() {
    }
}

Exception in thread "main" java.lang.ClassCastException: org.dom4j.tree.DefaultElement
   at org.hibernate.type.EntityType.toLoggableString(EntityType.java:134)
   at org.hibernate.type.ComponentType.toLoggableString(ComponentType.java:283)
   at org.hibernate.pretty.MessageHelper.infoString(MessageHelper.java:68)
   at org.hibernate.engine.EntityKey.toString(EntityKey.java:77)
   at java.lang.String.valueOf(Unknown Source)
   at java.lang.StringBuffer.append(Unknown Source)
   at org.hibernate.util.StringHelper.toString(StringHelper.java:168)
   at org.hibernate.loader.Loader.getRow(Loader.java:760)
   at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:293)
   at org.hibernate.loader.Loader.doQuery(Loader.java:387)
   at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:206)
   at org.hibernate.loader.Loader.loadCollection(Loader.java:1360)
   at org.hibernate.loader.collection.OneToManyLoader.initialize(OneToManyLoader.java:107)
   at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:488)
   at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
   at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1353)
   at org.hibernate.type.CollectionType.getCollection(CollectionType.java:470)
   at org.hibernate.type.CollectionType.resolveKey(CollectionType.java:327)
   at org.hibernate.type.CollectionType.resolve(CollectionType.java:321)
   at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:105)
   at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:492)
   at org.hibernate.loader.Loader.doQuery(Loader.java:411)
   at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:206)
   at org.hibernate.loader.Loader.doList(Loader.java:1515)
   at org.hibernate.loader.Loader.list(Loader.java:1498)
   at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:369)
   at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:266)
   at org.hibernate.impl.SessionImpl.list(SessionImpl.java:788)
   at org.hibernate.impl.QueryImpl.list(QueryImpl.java:74)
   at com.test.importexport.Data.getData(Data.java:55)
   at com.test.importexport.Data.executeExport(Data.java:34)
   at com.test.Main.main(Main.java:20)

Hibernate: select users0_.USER_NAME as USER1_, users0_.FIRST_NAME as FIRST2_0_, users0_.LAST_NAME as LAST3_0_ from users users0_
Hibernate: select addressess0_.USER_NAME as USER2___, addressess0_.ADDRESS_ID as ADDRESS1___, addressess0_.ADDRESS_ID as ADDRESS1_0_, addressess0_.USER_NAME as USER2_0_, addressess0_.STREET as STREET1_0_, addressess0_.CITY as CITY1_0_, addressess0_.REGION as REGION1_0_, addressess0_.COUNTRY as COUNTRY1_0_ from addresses addressess0_ where addressess0_.USER_NAME=?