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I'm trying to achieve something like the following, using the JPA Criteria API: SELECT b FROM Box b JOIN SpecialItem s WHERE s.specialAttr = :specialAttr The objects are Box @Entity public class Box implements Serializable { ... @ManyToOne @JoinColumn( name = "item_id" ) Item item; ... } Item @Entity @Inheritance( strategy = InheritanceType.JOINED ) public class Item implements Serializable { @Id private String id; ... } SpecialItem @Entity public class SpecialItem extends Item { private String specialAttr; ... } My attempt EntityManager em = getEntityManager(); CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery cq = cb.createQuery( Box.class ); Root from = cq.from( Box.class ); // Nothing to specify SpecialItem over Item! Join join = from.join("item", JoinType.LEFT); // java.lang.IllegalArgumentException: Unable to // resolve attribute [specialAttr] against path [null] Path p = join.get( "specialAttr" ); Predicate predicate = cb.equal( p, "specialValue" ); cq.where( predicate ); Not surprisingly it throws an exception because specialAttr isn't a member of class Item. How can I return all the Box es that contain a SpecialItem , where the SpecialItem.specialAttr has some value?

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