Entity mapping not working as expected for non-PK referencedColumnName in JoinColumn

Description

In an entity, I have a @ManyToOne mapping with a non-PK referencedColumnName and I’m trying to map the target entity into an entity view. Here is an attempt to simplify the setup:

@Entity
public class Cat {
    @Id
    private Long id;
    private String name;
    @ManyToOne
    @JoinColumn(referencedColumnName = "code")
    private CatFood favoriteFood;
}

@Entity
public class CatFood extends AbstractBaseEntity implements Serializable
{
    @Id
    private Long id;
    @Column(nullable = false, unique = true)
    private Long code;
    private String brand;
}

@EntityView(Cat.class)
public interface CatView
{
    @IdMapping
    Long getId();
    String getName();
    @Mapping("favoriteFood")
    CatFood getFavoriteFood();   
}

        ID NAME         FAVORITEFOOD_CODE
---------- ------------ -----------------
         1 Lucy           23
         2 Tom             1
         3 Kitty                                                                               


        ID BRAND        CODE
---------- ------------ ----------
         1 Whiskas           23
         2 Purina             1

Expected behavior

When the entity is queried directly, the favorite food should be loaded:

Cat cat = cbf.create(em, Cat.class).where("id").eq(2L).getSingleResult();
assertThat(cat.getFavoriteFood(), is(not(nullValue())));
assertThat(cat.getFavoriteFood().getBrand(), is("Purina"));

When the entity view is queried, the favorite food should also be loaded:

CriteriaBuilder<Cat> cb = cbf.create(em, Cat.class).where("id").eq(2L);
CriteriaBuilder<CatView> viewBuilder = evm.applySetting(EntityViewSetting.create(CatView.class), cb);
CatView catView = viewBuilder.getSingleResult();
assertThat(catView .getFavoriteFood(), is(not(nullValue())));
assertThat(catView .getFavoriteFood().getBrand(), is("Purina"));

Actual behavior

When querying the Cat entity directly, the behavior is as expected. For the catView though, getFavoriteFood() returns null.

Worse, in my original and much more complex setup the method corresponding to getFavoriteFood() in this example returns the wrong entity if the “food code” in the FK column matches another row with an “id” of the same value. Unfortunately, I couldn’t reproduce this exact behavior with the simplified setup.

Environment

Version: 1.6.3 JPA-Provider: Hibernate 5.5.7.Final DBMS: Oracle Application Server: Apache Tomcat, Spring Framework

[cgraefe]

Thanks again for your help and effort!

Ultimately, it will be better to use entity views all the way though because you can then fully control what is fetched and how, which entities not necessarily allow in all cases.

Generally, I agree! In my particular case, I am using Blaze Persistence to improve a large existing code base with some parts dating back more than 10 years. Being able to (at least temporarily) map entities into views is a nice feature that allows for a more gradual refactoring, imho.

[cgraefe]

Good to know, at least. Thanks for looking into this!