This issue is not resolved with 4 th version.

The proposition made by a JSR 317 member (on this link http://hwellmann.blogspot.com/2010/07/jpa-20-mapping-map.html) to use @MapKeyColumn with insertable = false and updatable = false doesn't work with Hibernate neither.

This leads to another issue wich is MappingException: Repeated column in mapping for collection

This seem to work with OpenJPA and EclipseLink