Much noise has been made in recent years about functional languages, like Scala or Haskell, and their benefits relative to object-oriented languages, most notably Java. Unfortunately, as wonderful as many of those benefits are, the fact remains that most Java developers will either not want or not be able to adopt those languages for writing day-to-day code. Which leaves us with a basic question: if I can't use these functional languages to write production code, is there any advantage to learning about them? The short answer is yes, for the fundamental premise--"I can't use functional code on my Java project"--is flawed. Java developers can, in fact, make use of functional ideas, and what's better, they don't even have to reinvent them for Java--thanks to the FunctionalJava library, many of the core primitives--interfaces that serve as base types for creating function values, for example--already exist, ready to be used.

In this presentation, we'll go over some basic functional concepts, then start seeing how they apply in the FJ library, and show how to use FJ and functional ideas on common Java programming tasks. Let the excuse "I can only use Java" finally be consigned to the rubbish bin, once and for all.