Why does java, c #, python, c ++ and others have no GUI as HTML inside the SoloLearn application?

Question

I see that inside the application, only HTML and a programming language javascript, can be united, to have both the visual part (HTML) and the functional part (JavaScript), but it is different from other languages, where it has only the functional , and no GUI, why? Will not rendering graphical interfaces for these languages ​​support most of the mobile phones we currently have? In the future, can we program these languages ​​on mobile devices with graphical interfaces?

Answer 1

this others languages ard executed at serverside, not in client as html in browser, I can image how your c++ code is running at server where displays window with buttons and server send this screenshot to your mobile, (still without interactivity), then you can try image what happens if this server run 10000 user codes in one minit with their GUIs how each of it wait for click on button and keep their memory.