From https://hibernate.atlassian.net/browse/HHH-15698:

We’ve deprecated the hbm.xml format without providing any replacement way to map a class with two different entity names. We have jumped through hoops in our APIs and internal implementation to support this usage.

Actually, just how deprecated is it really? Sure, we don't really document it, but nor do we document orm.xml. The documentation is basically completely silent on the subject of XML-based mappings and you're supposed to do them.

There's no straightforward way out of this, either:

• we un-deprecate hbm.xml, since it's the only way to specify an explicit entity name,
• introduce a brand new XML mapping format, derived from orm.xml, but with the ability to specify entity names for entities and associations, or
• we deprecate the remaining methods of Session that accept a string entityName, since they’re only useful with the deprecated hbm.xml mapping format.

Note that it would not help to introduce new annotations, since you can’t define multiple mappings for a single class in annotations. (Nor you can you define mappings for Maps.)

So what we’re contemplating here is losing:

1. the ability to map a class multiple times with different entity names, and
2. the ability to persist a Map.