Java needs an environment that can generate, parse and rearrange Java code in a way that vimscript just isn't suited for. Even in Emacs it's a Herculean effort

Java needs an environment that can generate, parse and rearrange Java code in a way that vimscript just isn't suited for. Even in Emacs it's a Herculean effort to make the editor understand Java at a deep enough level. Generally, if the language you're using co-evolved with a particular editor, use that editor, not vim. (That's not limited to Java.) On the other hand, C as a language grew up alongside vi, as well as the Unix environment it leverages so well. Languages with a nice REPL, like Python and Ruby, also are concise and flexible enough that any text editor will do; the languages are meant to work well enough with minimal editing capabilities. In those cases, vim is still great, because it's optimized for rearranging text of any kind.