IMHO Chapter 3.7.4.2 of the JPA spec says that @NamedEntityGraph can be used instead of fetch joins. For instance:
@Entity
@Table(name = "kunde")
@DiscriminatorColumn(name = "art", length = 1)
@NamedQueries(

// 2 concrete classes are derived from the abstract class
@PersistenceContext
private EntityManager em;
...
List<AbstractKunde> kunden =
em.createNamedQuery("...", AbstractKunde.class)
.setParameter("...", "...")
.setHint("javax.persistence.loadgraph", "bestellungen");
.getResultList();

When I try to access the attribute "bestellungen" after committing the transaction, then I get a LazyInitializationException.