Java: How to implement the interface?

How do I implement a Java interface in Clojure

• How do I create a Clojure object that implements this interface and then gets called from Java code? public interface Doer { public String doSomethin(String input); } Doer clojureDoer = ?; String output = clojureDoer.doSomethin(input);

• Answer:

  With proxy See the proxy macro. http://clojuredocs.org/clojure_core/clojure.core/proxy have some examples. It's also covered on http://clojure.org/java_interop#Java%20Interop-Implementing%20Interfaces%20and%20Extending%20Classes page. (proxy [Doer] [] (doSomethin [input] (str input " went through proxy"))) proxy returns an object implementing Doer. Now, to access it in Java you have to use gen-class to make your Clojure code callable from Java. It's covered in an answer to the https://stackoverflow.com/questions/2181774/calling-clojure-from-java question. With gen-class (ns doer-clj (:gen-class :name DoerClj :implements [Doer] :methods [[doSomethin [String] String]])) (defn -doSomethin [_ input] (str input " went through Clojure")) Now save it as doer_clj.clj, mkdir classes and compile it by calling in your REPL (require 'doer-clj) (compile 'doer-clj). You should find DoerClj.class ready to be used from Java in classes directory