Java JPA - OneToOne Relation between Entities not working

Question

Licitatie Entity:

@Entity
@Table(name="licitatie")
public class Licitatie implements Serializable {
    ...

    //bi-directional one-to-one association to Licitatie
    @OneToOne(mappedBy="licitatie")
    private Produs produs;

    ...
}

Produs Entity:

@Entity
@Table(name="produs")
//@DiscriminatorColumn(name="id", discriminatorType=DiscriminatorType.INTEGER)
@MappedSuperclass
public class Produs implements Serializable {
    ...

    //bi-directional one-to-one association to Produs
    @OneToOne
    @JoinColumn(name="licitatie_id")
    private Licitatie licitatie;

    ...
}

Database:

Licitatie:

id  start   status
1   5   open
2   5   open
3   5   open

Produs:

id  licitatie_id    DTYPE   description
1   1           Carte   ...
2   2           Carte   ...
3   3           Carte   ...

After I run tris query: "SELECT t FROM Licitatie t" , the attribute Product from object of type Licitatie is null. But there are records in tables.

What I'm doing wrong?

* EDIT *

After I get data from table, calling getProdus() return this message:

{IndirectSet: not instantiated}

Answer 1

SOLVED

I've added column PRODUS_ID to licitatie table.

Licitatie: id produs_id ... Produs: id, licitatie_id ...