title: How to require a jar file in Clojure REPL?
body: <p>It's easy to <code>require</code> a package from clojure:</p>
  
  <pre><code>user=&gt; (require 'clojure.core)
  nil
  </code></pre>
  
  <p>But how can I require a <code>.jar</code> file inside Clojure?  </p>
  
  <p>(I'm trying to learn <code>lein</code>. Leiningen is useful to big projects rather than small scripts. So I want to figure out that what's the best method to use a <code>jar</code> package in my Clojure scripts and in REPL.)</p>