You only have to call ANT directly when you want to build the zip file. Otherwise the SDK is built using the gradle build script but that also calls the ANT script, which works great as ANT is a first class citizen in gradle. I don’t really see a reason to build the SDK itself with gradle only given that I’d lose all the setup abilities for platform projects in NetBeans and I would have to create scripts for generating NBMs, config files, layer files etc in gradle.