Upon further reflection, I've concluded that this isn't necessarily a bug in the converters (they're free to return a positive score for a null target Variant if they want), but rather a bug in ServerResource.doConditionalHandle.
If content negotation is in strict mode and getPreferredVariant() returns null, then I think that doConditionalHandle should call doError (Status.CLIENT_ERROR_NOT_ACCEPTABLE). I logged an issue with this proposed fix: https://github.com/restlet/restlet-framework-java/issues/568 ------------------------------------------------------ http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=2948057
