They have javadoc - see the interface: https://github.com/aerogear/aerogear-unifiedpush-server/blob/2479628a9bad6f7dd572bdc020b3d8e748492271/src/main/java/org/jboss/aerogear/unifiedpush/service/GenericVariantService.java

I never do the same JavaDoc on the impl files, again (hence we use the ```@Override```)