Monkeybars is a JRuby library that gives Ruby developers easy access to the world of Swing GUI development. Much of the complexity of Swing is removed and appropriately Ruby-ized. There is an emphasis on testability and better decomposition of apps that are historically notoriously difficult to test. This talk will focus on presenting the Monkeybars library and walking through its usage in building a small GUI application. I will show interfacing with Swing components, using GUI builder tools to create a layout and packaging of the application for distribution as an executable jar file, a Windows exe file and an OSX .app bundle. Along the way I will show how Monkeybars decouples app logic from view code and the mechanisms that are in place to automate the repetitive tasks involved in GUI development. I will also touch on the general structure of a JRuby application and the problems faced when bridging the two worlds. At the conclusion, attendees will have a good idea of what’s involved in creating a GUI using Monkeybars and hopefully will have a better understanding of how to leverage Java libraries from their Ruby applications.