I think you're missing the point if you want this. Boot once, leave running, swap in new code, interact. A clj process (like most lisps) is alive and dynamic in more ways than you might be used to. There's no need to be constantly booting it.

Try Planck if you're on OS X: https://github.com/mfikes/planck

Thanks, but i also need my applications to be portable :S

Alright, how about running it on Node then? I assume this is mostly for scripting, as long running servers and the like wouldn't need to be concerned with start-up times.

That might be a solution, yes. But Node is a single-threaded engine, so I'm not sure if I can run parts of Clojure which use multiple threads, or if there are other restrictions.

Anything that uses the JVM will never (at least for a long time) achieve the startup time of cpython, cruby or node, less of ls and grep, so don't get your hopes up :) - that said, most of clojure's startup problems lie in clojure itself and not the JVM.

On modern hardware Clojure starts in under a second. I write simple support scripts in Clojure all the time.