Well, if by "jump" you mean to switch to another language as your 'default' language, then
you should make the jump when you need it. Different languages are good for different applications.
You can program games equally well in C++ as you can in
Java. Usually C++ has preference for most companies because it allows you access to hardware more easily. However, there are plenty of abstraction layers which allow you to do 3D programming in Java.
If you want to educate yourself in a language though, it's best to do it *now*. Pick a language, and just do it. I'm very curious about declarative languages, so lately I've been working with languages such as Haskell and Lisp.