A very nice—and extremely underused—feature of the static metamodel is the ability to write:

@OneToMany(mappedBy=Item_.ORDER)
Set<Item> items;

which is a lot more typesafe than:

@OneToMany(mappedBy="order")
Set<Item> items;

But we could take this further. We could have the static metamodel include string-valued constants for named queries, named entity graphs, and even SQL result set mappings.

So you could write, for example:

em.createQuery(Book_.QUERY_ALL_BOOKS).getResultList();

Hibernate 6.3 already supports this.