Using Java jar in Clojure+

Question

I am new to clojure. I am trying to use java jar in clojure, but it doesn't seem to work. I have built the path, put the jar physically in the lib folder of the project and tried :

(import 'jml.clustering.NMF)

But i get this exception :

ClassNotFoundException jml.clustering.NMF java.net.URLClassLoader.findClass (:-1)

How do i fix this? Thank you in advance.

Related: leiningen - how to add dependencies for local jars

DaoWen
– DaoWen

2015-04-12 03:44:45 +00:00
Commented Apr 12, 2015 at 3:44 — DaoWen
– DaoWen, Commented Apr 12, 2015 at 3:44

DaoWen · Accepted Answer · 2015-04-11 18:24:31Z

1

Just sticking the jar in the lib directory won't force leiningen to include the jar in the classpath. Instead, try adding the library to your project's dependencies list:

:dependencies [[org.clojure/clojure "1.6.0"]
               [org.realityforge.jml/jml "0.9.3"]]

You can find the group/id and version of available libraries by searching one of the supported public repositories. I searched maven.org for jml to find the info I used above.

Note that this doesn't use your local copy of the jar, but rather downloads a new one from the repository and caches it somewhere. This might not be ideal, but for my own projects I've found that getting lein to use a local jar is just way too big of a headache. Using one from clojars or maven.org is so much simpler that I can overlook having to download a new copy.

answered Apr 11, 2015 at 18:24

DaoWen

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4 Comments

Savas Over a year ago

Thank you for clarification :) , this would probably work, but this isn't the jml I'm trying to use, and as I see the one i require is not registered at maven.org :( My headache continues... Thanks anyway.

noisesmith Over a year ago

If you use mvn to install the version you need to your local cache, lein will be able to find it there.

DaoWen Over a year ago

@Savas - lein makes it really hard to use anything that's not in a public repository. I think they actually do this purposely, because they want to encourage developers to make it easy for other people to copy a project and get it working on a different system. I posted a link to another related question in a comment above. I hope that helps.

Savas Over a year ago

Thank you all. All of your suggestions helped and i used this link elangocheran.com/blog/2013/03/… also to resolve my problem. I created an additional one for myself before when i named my user using, among other characters, this one "&", so it was very "fun" playing with cmd.

Édipo Féderle · Accepted Answer · 2015-04-14 20:16:04Z

0

If the JAR is your own, you can follow these steps to use a local JAR not available in any maven repository.

Given a Jar: foo.jar

Into your Clojure project dir:

mvn deploy:deploy-file -DgroupId=local -DartifactId=foo \
 -Dversion=1.0.0 -Dpackaging=jar -Dfile=foo.jar \
 -Durl=file:repo

Edit your project.clj to include the new dependency:

 [local/foo "1.0.0"]

answered Apr 14, 2015 at 20:16

Édipo Féderle

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