@Entity
@Table(name = "account")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "type")
public abstract class BaseAccountPojo
{
   @Id
   @GeneratedValue
   @Column(name = "account_id")
   public Long accountId;
}

@Entity
@DiscriminatorValue("cust")
public class CustAccountPojo extends BaseAccountPojo
{
   @OneToOne
   @PrimaryKeyJoinColumn
   public CreditCardPojo creditCard;

   @OneToMany(mappedBy = "owner")
   public Set<EndCustAccountPojo> endCustAccounts = new HashSet<EndCustAccountPojo>();
}

@Entity
@DiscriminatorValue("endCust")
public class EndCustAccountPojo extends BaseAccountPojo
{
   @OneToOne
   @PrimaryKeyJoinColumn
   public CreditCardPojo creditCard;

   @ManyToOne
   @JoinColumn(name = "owner_id")
   public CustAccountPojo owner;
}

@Entity
@Table(name = "credit_card")
public class CreditCardPojo
{
   @Id
   @GeneratedValue
   @Column(name = "account_id")
   public Long accountId;
}

session.get(EndCustAccountPojo.class, 1L);

Hibernate:
    select
        endcustacc0_.account_id as account2_0_2_,
        endcustacc0_.owner_id as owner3_0_2_,
        custaccoun1_.account_id as account2_0_0_,
        creditcard2_.account_id as account1_1_1_
    from
        account endcustacc0_
    left outer join
        account custaccoun1_
            on endcustacc0_.owner_id=custaccoun1_.account_id
    left outer join
        credit_card creditcard2_
            on custaccoun1_.account_id=creditcard2_.account_id
    where
        endcustacc0_.account_id=?
        and endcustacc0_.type='endCust'
Hibernate:
    select
        creditcard0_.account_id as account1_1_0_
    from
        credit_card creditcard0_
    where
        creditcard0_.account_id=?