Delegated classes and JPA/Hibernate

Support
4

Found the solution!
It’s obvious now, but the problem was that I was using JPA field annotation instead of accessor. It all made sense after having a look at the bytecode that Kotlin was generating for the TestMixin class.

This is the updated solution:

interface TestTrait {
    @get:Column
    var traitValue: Int
}


class TestTraitImpl : TestTrait {
    override var traitValue: Int = 0
}


@MappedSuperclass
class TestMixin :
        TestTrait by TestTraitImpl() {
    @get:Column
    var mixinValue: Int = 0
}


@Entity
@Table
public class TestEntity extends TestMixin {

    private UUID id;
    private int entityValue;

    @Id
    @GeneratedValue
    @Type(type = "uuid-char")
    public UUID getId() {
        return id;
    }

    public void setId(UUID id) {
        this.id = id;
    }

    @Column
    public int getEntityValue() {
        return entityValue;
    }

    public void setEntityValue(int entityValue) {
        this.entityValue = entityValue;
    }
}

I always preferred field annotation over accessor, but being able to use composition on my JPA entities is much more important!