One reason why I like Java is that it is easy to package up Java code and use with other JVM languages like JRuby, Clojure, and Scala.

Here is an example using a Makefile (works on Max OS X and Linux - for Windows developers, it would be great if someone would provide me with a Windows .bat command file) to build a JAR file and using it in a small JRuby test program

make jar
jruby test.rb

This is a simple example with a tiny amount of training data. The Java code that this example uses can be used to train very large networks but you must increase the number of training iterations.