CriteriaQuery join fetch not executed for @Embeddable with @OneToMany in Hibernate

Environment

• Red Hat JBoss Enterprise Application Platform (EAP) 6
• Hibernate 4

Issue

• A @OneToMany association exists from a "parent" to a "child" type through an @Embeddable

@Entity
public class ChildEntity implements Serializable {
    ...
}

@Embeddable
public class EmbeddedEntity implements Serializable {
    @OneToMany( cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "PARENT_GUID")
    private Set<ChildEntity> children;
    ...
}

@Entity
public class ParentEntity implements Serializable {
    @Id
    private String guid;

    @Embedded
    private EmbeddedEntity embedded;
    ...
}

• A CriteriaQuery is constructed as follows (using hibernate-jpamodelgen properties)

CriteriaBuilder cb = entityManager.getCriteriaBuilder();

CriteriaQuery<ParentEntity> cq = cb.createQuery(ParentEntity.class);
Root<ParentEntity> root = cq.from(ParentEntity.class);
root.fetch(ParentEntity_.embedded).fetch(EmbeddedEntity_.children); // specify join fetch
cq.where(cb.equal(root.get(ParentEntity_.guid), "P1"));

TypedQuery<ParentEntity> typeQuery = entityManager.createQuery(cq);

• The generated query omits the join fetch (as evident in looking at the generated SQL)
• The association is not initialized and requires a subsequent query

Resolution

• Use an HQL based query to perform the join fetch
• The issue will be corrected in a future release

Root Cause

This is a This content is not included.defect¹ in the Hibernate CriteriaQuery implementation

Diagnostic Steps

Enable Hibernate SQL trace

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