In theory, literally anything can be done in any programming language (assuming it is turing complete). The question is rather why you want to do this, after all there's already quite a few osu! clients (stable, lazer, opsu, McOsu, oshu just to name a few). If you want to do development for this game, i highly encourage you to contribute to osu!lazer instead, which is going to replace stable soon(tm).
