Specifies a custom HQL/JPQL query to be used in place of the default SQL generated by Hibernate when an entity or collection is fetched from the database by id. This occurs when:

• an association to an entity is fetched lazily,
• a collection is fetched lazily, or
• when an entity is retrieved using org.hibernate.Session#get or org.hibernate.Session#find.

The given HQL query must have exactly one parameter which accepts the id of the entity or of the entity which owns the collection. It must return a single item in the select list, and that item must be the correct type of entity or collection element.