First part will be a a gentle introduction, with examples, to the forthcoming Java Platform Module System. Learn how to create a module from scratch, compile it, test it, and run it. This session will also show basic techniques for modularizing existing libraries and applications. Second part : Modularizing an existing library or application, or creating new modules from scratch, can raise many difficult and subtle design issues. This session will present a set of principles for modular development, with examples taken from the JDK itself.