Running a JAR file created by Leiningen

Question

I have the following code in the file project.clj:

(defproject pinger "0.0.1-SNAPSHOT"
  :description "A website availability tester"
  :dependencies [[org.clojure/clojure "1.3.0"]]
  :main pinger.core)

(ns pinger.core
  (:import (java.net URL HttpURLConnection))
  (:gen-class))

(defn response-code [address]
  (let [conn ^HttpURLConnection (.openConnection (URL. address))
    code (.getResponseCode conn)]
    (when (< code 400)
      (-> conn .getInputStream .close))
    code))

(defn available? [address]
  (= 200 (response-code address)))

(defn -main []
  (let [addresses '("http://google.com"
            "http://amazon.com"
            "http://google.com/badurl")]
    (while true
      (doseq [address addresses]
    (println (available? address)))
      (Thread/sleep (* 1000 60)))))

I create an uberjar:

C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\code\src
\pinger>lein uberjar
Cleaning up.
Copying 1 file to C:\Documents and Settings\vreinpa\My Documents\Books\Programmi
ngClojure\code\src\pinger\lib
Warning: *classpath* not declared dynamic and thus is not dynamically rebindable
, but its name suggests otherwise. Please either indicate ^:dynamic *classpath*
or change the name.
Copying 1 file to C:\Documents and Settings\vreinpa\My Documents\Books\Programmi
ngClojure\code\src\pinger\lib
Created C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\
code\src\pinger/pinger-0.0.1-SNAPSHOT.jar
Including pinger-0.0.1-SNAPSHOT.jar
Including clojure-1.3.0.jar
Created C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\
code\src\pinger/pinger-0.0.1-SNAPSHOT-standalone.jar

I then try to run that uberjar and get the following error:

C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\code\src
\pinger>java -jar pinger-0.0.1-SNAPSHOT-standalone.jar
Exception in thread "main" java.lang.NoClassDefFoundError: pinger/core
Caused by: java.lang.ClassNotFoundException: pinger.core
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: pinger.core. Program will exit.

What am I doing wrong here?

Answer 1

As I said in response to your other question, the project.clj file is not the place to put source code - project.clj is loaded by leiningen to set up your project configuration and putting arbitrary code there is not guaranteed to work at all, and will certainly mess up the loading of namespaces you defined in there. follow the conventions for source libs and put the files under the src directory in your project tree.

Answer 2

$ lein new pinger
$ cd pinger
$ lein deps

pinger/project.clj

(defproject pinger "0.0.1-SNAPSHOT"
  :description "A website availability tester"
  :dependencies [[org.clojure/clojure "1.3.0"]]
  :main pinger.core)

pinger/src/pinger/core.clj

(ns pinger.core
  (:import (java.net URL HttpURLConnection))
  (:gen-class))

(defn response-code [address]
  (let [conn ^HttpURLConnection (.openConnection (URL. address))
    code (.getResponseCode conn)]
    (when (< code 400)
      (-> conn .getInputStream .close))
    code))

(defn available? [address]
  (= 200 (response-code address)))

(defn -main []
  (let 
    [addresses
      '("http://google.com"
        "http://amazon.com"
        "http://google.com/badurl")]
  (while true
    (doseq [address addresses]
      (println (available? address)))
    (Thread/sleep (* 1000 60)))))

$ cd pinger
$ lein uberjar

absolute path
$ java -jar /vagrant/MyClojure/pinger/target/pinger-0.0.1-SNAPSHOT-standalone.jar

or

relative path from project.clj
$ java -jar ./target/pinger-0.0.1-SNAPSHOT-standalone.jar