@Entity
@PersistenceUnit(unitName="smartbo")
@Table(name = "ISS_ACCT_TAB")
public class AccountBO implements Serializable
{
   private static final long serialVersionUID = 1771063352348052795L;

   public AccountBO()
    {
        super();
    }

   @Id
   @Column(name="ACCT_NUM")
   private String accountNum;

   @ManyToMany(fetch = FetchType.EAGER)
   @JoinTable(
                name = "ISS_REF_TAB",
                joinColumns = {@JoinColumn(name = "ISS_ACCT_NUM", referencedColumnName = "ACCT_NUM")},
                inverseJoinColumns = {@JoinColumn(name = "ISS_CARD_NUM", referencedColumnName = "CARD_NUM")}
             )
       private List<CardBO> cards = new ArrayList<CardBO>();

   public String getAccountNum() {
      return accountNum;
   }

   public void setAccountNum(String accountNum) {
      this.accountNum = accountNum;
   }

   public List<CardBO> getCards() {
      return cards;
   }

   public void setCards(List<CardBO> cards) {
      this.cards = cards;
   }
}


@Entity
@PersistenceUnit(unitName="smartbo")
@Table(name = "ISS_CARD_TAB")
public class CardBO implements Serializable
{
   private static final long serialVersionUID = 7411289056455489513L;


    public CardBO()
    {
        super();
    }

   @Id
   @Column(name="CARD_NUM")
   private String cardNumber;
   
   @ManyToOne(fetch = FetchType.EAGER)
   @JoinTable(
                name = "ISS_REF_TAB",
                joinColumns = {@JoinColumn(name = "ISS_CARD_NUM", referencedColumnName = "CARD_NUM")},
                inverseJoinColumns = {@JoinColumn(name = "ISS_PERSON_ID", referencedColumnName = "PERSON_ID")}
             )
       private PersonBO person = new PersonBO();

   public String getCardNumber() {
      return cardNumber;
   }

   public void setCardNumber(String cardNumber) {
      this.cardNumber = cardNumber;
   }

   public PersonBO getPerson() {
      return person;
   }

   public void setPerson(PersonBO person) {
      this.person = person;
   }
}


@Entity
@PersistenceUnit(unitName="smartbo")
@Table(name = "PERSON_TAB")
public class PersonBO implements Serializable
{

   private static final long serialVersionUID = -3065605114940266756L;

   public PersonBO()
    {
        super();
    }

   @Id
   @Column(name="PERSON_ID")
   private String personId;

   public String getPersonId() {
      return personId;
   }

   public void setPersonId(String personId) {
      this.personId = personId;
   }
}

Query qry = _emBO.createQuery("SELECT " +
         "f.cards " +
         "FROM " +
            "AccountBO f " +
         "WHERE " +
         "f.accountNum = ?");

   cardsBO = qry.getResultList();