ejb

@Entity
public class Person implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String name;
    @OneToOne
    private Person test;


@Entity
public class PersonGroup implements Serializable {

    private static final long serialVersionUID = 1L;

    public enum PersonType{MALE,FEMALE}

    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private PersonType personType;
    @OneToMany(cascade = { CascadeType.ALL }, fetch = FetchType.EAGER)
    private Collection<Person> persons = new Vector<Person>();


@Entity
@Table(name="pairs")
public class Pair implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    @OneToOne
    private Person personA;
    @OneToOne
    private Person personB;