Why is leiningen so slow when it starts?

Question

I\'m using lein repl to execute clojure repl in console. When I run it, it takes over 15 seconds. When I run java -cp clojure-1.6.0.jar clo

Answer 1

In my case it was the cider-nrepl plug-in that significantly contributed to the load time.

Quick unscientifical research with jvisualvm showed that good deal of time goes into loading & evaluating the files (0.10-snapshot is not AOT-ed) and there was also init logic that scans the classpath.

Using fast trampolines halved the start-up time.

The jvm plays no bigger role than the OS or the file system in my opinion. It's all about the code being loaded.