Question

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 1

reify is strongly preferred for implementing interfaces – proxy is heavy-duty, old, and slow, so should be avoided when possible. An implementation would look like:

(reify Doer
  (doSomethin [this input]
    (...whatever...)))