@Entitiy
@Table(name="T_ORGANIZATION")
public class Organization {

     private int organizationId;
     private Collection childOrganizations;

     @Id
     @GeneratedValue
     @Column(name="organization_id")
     public int getOrganizationId() {
         return this.organizationId;
     }

     public void setOrganizationId(int id) {
         this.organizationId = id;
     }

     // Assume this is mapped correctly
     public Collection getChildOrganizations() {
         return this.childOrganizations;
     }

     public void setChildOrganizations(Collection children) {
          this.childOrganizations=children;
     }

     // Assume equals() and hashCode() are overriden here
}