what coding language does apple use
Judging for the closed-ness of Apple, you probably won't get much credible answer from Apple's own people. OS X and iOS are primarily written in Objective-C with some C++ in between (e.g. IOKit, WebKit, etc) and probably some C as well for the kernel stuff. However looking at Apple's software engineering jobs vacancies [1], these are also relevant programming languages at Apple: Java.