Emacs features vary wildly in support from language to language - in Go, for instance, it's very easy to get both those working, while in Java it requires somet

Emacs features vary wildly in support from language to language - in Go, for instance, it's very easy to get both those working, while in Java it requires something more complicated such as eclim. company-mode is by far the best completion frontend, but the quality of the completions is dependent on how good the backend is, which varies a lot.