<hibernate-mapping>

  <class name="Student">

    <id name="id">
      <generator class="native"/>
    </id>

    <property name="name" not-null="true"/>

    <set name="addresses" cascade="all-delete-orphan">
     <key column="id_student" not-null="true"/>
     <composite-element class="Address">
       <property name="street" not-null="true"/>
       <property name="city" not-null="true"/>
       <property name="state" not-null="true"/>
       <property name="zip" not-null="true"/>
       <many-to-one name="attach" column="id_attach" unique="true" cascade="all,delete"/>
     </composite-element>     
    </set>
   
  </class>

  <class name="Attach">
    <id name="id">
      <generator class="native"/>
    </id>   
  </class>

</hibernate-mapping>

public class Student implements Serializable {

    private Integer id;

    private String name;

    private Set<Address> addresses;

    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 Set<Address> getAddresses() {
        return addresses;
    }

    public void setAddresses(Set<Address> addresses) {
        this.addresses = addresses;
    }   

}

public class Address implements Serializable {

    private Integer id;

    private String street;

    private String city;

    private String state;

    private String zip;

    private Attach attach;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public String getZip() {
        return zip;
    }

    public void setZip(String zip) {
        this.zip = zip;
    }

    public Attach getAttach() {
        return attach;
    }

    public void setAttach(Attach attach) {
        this.attach = attach;
    }

}

public class Attach implements Serializable {

    private Integer id;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

}

/* Insert the entity Student. */

session.beginTransaction();
Student student = new Student();
student.setName("Rafael Santini");
student.setAddresses(new HashSet<Address>());
Address address = new Address();
address.setStreet("Avenida das Nações Unidas");
address.setCity("Capivari de Baixo");
address.setState("Santa Catarina");
address.setZip("88745-000");
address.setAttach(new Attach());
student.getAddresses().add(address);
session.save(student);
session.getTransaction().commit();

/* Remove all addresses. */

session.beginTransaction();
for (Object obj : session.createQuery("from Student").list()) {           
    Student student = (Student) obj;
    student.getAddresses().clear();           
    session.saveOrUpdate(obj);
}
session.getTransaction().commit();