@Entity
@Inheritance
@DiscriminatorColumn(name = "art", length = 1)
public abstract class AbstractKunde implements Serializable {
   @Id
   @GeneratedValue
   @Basic(optional = false)
   private Long id;

   @OneToOne(mappedBy = "kunde", cascade = { PERSIST, REMOVE })
   @NotNull(message = "{...")
   private Adresse adresse;
   
   @OneToMany
   @JoinColumn(name = "kunde_fk", nullable = false)
   @OrderColumn(name = "idx", nullable = false)
   private List<Bestellung> bestellungen;
   ...
}

@Entity
@Inheritance
@DiscriminatorValue("F")
@Cacheable
public class Firmenkunde extends AbstractKunde {...}

...
@PersistenceContext
private EntityManager em;

public void deleteKundenOhneBestellungen() {
   // DELETE
   // FROM   AbstractKunde k
   // WHERE  k.bestellungen IS EMPTY
   CriteriaBuilder builder = em.getCriteriaBuilder();
   CriteriaDelete<AbstractKunde> criteriaDelete = builder.createCriteriaDelete(AbstractKunde.class);
   Root<AbstractKunde> kunden = criteriaDelete.from(AbstractKunde.class);
   Expression<List<Bestellung>> bestellungenPath = kunden.get(AbstractKunde_.bestellungen);
   Predicate pred = builder.isEmpty(bestellungenPath);
   criteriaDelete.where(pred);
   em.createQuery(criteriaDelete).executeUpdate();
}