I haven't checked on a more recent version, but on 1.0.3 a resource with the annotation:
@Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
will produce a content type of application/xml given the accepts header text/html,application/xml;q=0.9,*/*
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
produces application/json
By my reading of
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1 application/xml should end up with a q of 0.9, and application/json a q of 1 after matching */* in both cases.
Tom