Where can I switch to Java?

Sorry, I’ve literally just signed up to the website a few minutes ago and I don’t know much. I went on one of the missions and went onto my programming language selector and I couldn’t see Java on there, only Python, Javascript, CoffeeScript, Clojure and LUA. I know that this is probably a dumb question, and I apologize in advance.

Java is currently being added. However, it is not yet available.