Apologies if this is a bit daft, I just experimented with Java/Clojure interop and I think most people here are talking about Clojure/Java interop: note the different order. I built a Java 'application' that uses Java's rich libraries to handle all the "I/O stuff and interactions", and called out via clojure.api to a clojure functional core. This seemed to work very well.. But I can see this means learning two languages (not 1.5). Just wondering if many people do this?

Get the Java code to collect a bunch of abstract data values and feed it into the functional core, which is pure clojure with very few libraries at all.