How to add libraries in clojure?

Question

Everywhere I see, it is suggested that I add :dependencies in project.clj and run lein deps. Where are these downloaded? What is my CLASSPATH and how can I add my own JARs to my clojure project?

While the answer for

Dependencies in maven local repositories with leiningen

kind of solves my need, I am not marking it duplicate as what I am asking is much simpler (being a beginner, who does not have much experience with Java to know about Maven). I am still finding it hard to understand where clojure ends and leiningen begins.

The thing I was looking for is a way to add library like we do in most other languages (e.g. copy JAR to project directory and import in code).

Answer 1

This is great question since it's not clear at all. Leiningen is often a black hole and if something isn't working it's often hard to debug.

I just recently had to do some manual scripting and leiningen does help you with finding out these things.

Where are these downloaded?

The directory is in $HOME/.m2. This is Maven's: http://maven.apache.org/settings.html

What is my classpath?

The classpath is set depending on your :dependencies as well as your :source-paths and :resource-paths vectors.

You can find out your classpath like this:

lein classpath

This will print a huge list depending on your configuration.

You could --for instance-- then run a script:

    java -cp cljs-1.7.xx.jar:scripts:$(lein with-profile +dev-cljs classpath) clojure.main scripts/cljs-build.clj dev

That has access to all your projects dependencies and loads them properly.

Although you could use lein run to achieve something similar:

lein with-profile +dev-cljs run -m clojure.main scripts/cljs-build.clj dev

How do I add my own JARs?

See: leiningen - how to add dependencies for local jars?