JPA 2 Criteria Fetch Path Navigation

Question

With JPA 2 Criteria Join method I can do the following:

    //Join Example (default inner join)
    int age = 25;
    CriteriaBuilder cb = entityManager.getC         


        

Answer 1

Beginning with JPA 2.1, dynamic entity graphs can be used for fetching in criteria queries, while using join() instead of fetch(). From the example in the question:

//Join Example (default inner join)
int age = 25;
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery c = cb.createQuery(Team.class);
Root t = c.from(Team.class);
Join p = t.join(Team_.players);
c.select(t).where(cb.equal(p.get(Player_.age), age));
TypedQuery q = entityManager.createQuery(c);
List result = q.getResultList();

If this:

TypedQuery q = entityManager.createQuery(c);

is replaced with this:

EntityGraph fetchGraph = getEntityManager().createEntityGraph(Team.class);
fetchGraph.addSubgraph(Team_.players);
TypedQuery q = entityManager.createQuery(c).setHint("javax.persistence.loadgraph", fetchGraph);

then all players will be eager fetched.