See https://hibernate.zulipchat.com/#narrow/stream/132094-hibernate-orm-dev/topic/entity-name.20and.20HCANN

The idea would be to use the classes from org.hibernate.mapping to contribute the mapping of those entities to Hibernate ORM. It hasn’t been done, but should in theory be possible.

At the moment our only way to contribute that mapping to would be to cast the MetadataImplementor passed to AdditionalJaxbMappingProducer to a InFlightMetadataCollector. A bit dodgy, but enough to start experimenting.