One of the key goals of JavaServer Faes (JSF) 2.0 is ease of use, and component development is a prime example: all it takes is a single file. What does this mean? Now you can write a reusable widget with ease, whether it’s a single HTML element, a reusable panel, or a powerful Ajax widget. If you can’t express everything in a single Facelet template, that’s okay – you can add logic with either Groovy or Java. And don’t worry – JSF 2.0 lets you easily package and version resources (such as stylesheets, images, or JavaScript files) in libraries, which you can load from a JAR file, or from your web application. In this session, we’ll walk through the process of creating UI components with JSF 2.0, moving from a simple component to a more complicated Ajax widget, looking at all of the great facilities JSF 2.0 offers component developers. We’ll also discuss the new Ajax JavaScript API, which simplifies the process of writing Ajax components and facilitates interoperability between different Ajax component suites.