By the way, more topics like this should happen. :p Brilliant discussion topic, really.
I see absolutely NO situation where Java should ever be used over another language (e.g., C++), except if your purpose is very specifically aimed toward a Java game (RS), and even then, I wouldn't use Java still.
Also, C# is fine I suppose. I have nothing much against it, other than that Microsoft tries to make everyone use a lame Windows compiler and lame libraries. It is a pretty general purpose language though, which is nice (I've used it for wp7-related development and also just general computing stuff).
C++ > C, also.

