could leverage the new base endpoint code:
https://github.com/aerogear/aerogear-unifiedpush-server/blob/master/src/main/java/org/jboss/aerogear/unifiedpush/rest/registry/applications/AbstractVariantEndpoint.java

like this file does, for instance:
https://github.com/aerogear/aerogear-unifiedpush-server/blob/master/src/main/java/org/jboss/aerogear/unifiedpush/rest/registry/applications/AndroidVariantEndpoint.java