Clojure Programming Cookbook

Calling Clojure from Java

In this recipe, we will learn how to define Java classes in Clojure and call them from Java.

Getting ready

To include Java sources in a Leiningen project, we create the project.clj as follows and restart the REPL:

(defproject chapter05 "0.1.0-SNAPSHOT" 
  :description "FIXME: write description" 
  :url "http://example.com/FIXME" 
  :license {:name "Eclipse Public License" 
            :url "http://www.eclipse.org/legal/epl-v10.html"} 
  :java-source-paths ["src/java"] 
  :aot [chapter05.calling-from-java] 
  :prep-tasks [ 
               ["compile" "chapter05.calling-from-java"] 
               "javac" "compile" ] 
  :main chapter05.TestHello 
  :dependencies [[org.clojure/clojure "1.8.0"] 
                 ]) 

How to do it...

We will take a look at how we define Java classes that can be called from Java.

Defining ...