The core Crowd jar seems to have much more in it than is required to integrate a client. In particular, the hibernate mapping file at the root of the jar (which is unnecessary in making a client) gets picked up by Grails when included in a Grails project and Grails tries to create Hibernate domain objects for the listed mappings. Removing the hibernate mapping file from the jar works, but I think it would be nice to have a seperate, slimmed down Crowd-client.jar which only has what is required to get a client running.

More work, I know, but it would be nice...

Also, requirements for client integration are sparse, but that is addressed elsewhere.