Clojure / Lein / Package into Jar

Question

For the past 6 months, I have been running my Clojure app from the repl.

Ie, whenever I want to run the app, I load up a clojure repl, then I type in: (load-file "src/run.clj") ... and it runs my app.

Then, clojure loads up all of my *.clj files, compiles them, and runs.

I have recently switched over to Lein. I would like to "compile ahead of time / package up" my code, so that I can get a single jar, with Main method, and run it directly on the command line via "java ..." rather than having to load up a clojure/lein repl.

It's clear to me that I need to do some RTFMing. However, if someone could point me at a good tutorial, it would be much appreciated.

Thanks!

Answer 1

There is also a nice tutorial in the official lein tutorial . I'm just including this information in case we end up with any dead links in the future.

1) You first need to designate the main namespace by adding :main to project.clj

(defproject yourproject "0.1"
   :dependencies [[org.clojure/clojure "1.4.0"]]
   :main yourproject.core)

2) In your designated main namespace you must add (:gen-class) and you must designate the main function by using (defn -main ...)

(ns yourproject.core
  (:gen-class))

(defn -main [& args]
  (println "This is your crazy project!"))

3) run uberjar to create the standalone jar

lein uberjar

4) run your program with java -jar

java -jar yourproject.jar