I am looking for a way to develop for iOS using Java, but I need a system that is actually open source. libGDX is not open source in the iOS sense because it depends on the (now commercial) RoboVM library. The other one I found is, Codename One, which is also commerical. Is there any tool out there that is open source, or would I have to write my own bindings?
Recently, libGDX moved on to a new iOS backend, which is a fork of the RoboVM backend before it went commercial. The official RoboVM is gone as well because of company takeovers. libGDX has also added a new Multi-OS Engine backend as well that might suit some users' needs (although only in beta).