The reason there isn't demand is because the same tool for Java would necessarily be a lot slower on startup. The version of the tool that eliminates the slowdown by daemonizing does exist: it's called eclim.
Personally I sometimes use eclimd in Eclipse from emacs. But it's a bit flakey. Usually I switch between an IDE and emacs depending on whether the current task is text-intensive or not.
IMO the entire language-specific modes thing in emacs is a collection of hacks (eg.: using regexes for highlighting! highlighting as a characteristic of the text!) and woefully under-architected; this is a much bigger problem than lack of any language-specific tool. Until elisp is replaced with a faster language with less dynamic scope by default (Scheme would be fine), I don't really see it improving.
Personally I sometimes use eclimd in Eclipse from emacs. But it's a bit flakey. Usually I switch between an IDE and emacs depending on whether the current task is text-intensive or not.
IMO the entire language-specific modes thing in emacs is a collection of hacks (eg.: using regexes for highlighting! highlighting as a characteristic of the text!) and woefully under-architected; this is a much bigger problem than lack of any language-specific tool. Until elisp is replaced with a faster language with less dynamic scope by default (Scheme would be fine), I don't really see it improving.