Open Source Web Frameworks in Java

ZK is an AJAX-based, event-driven, XUL-compliant, all Java framework for enabling Web applications to have the rich user experiences. With intuitive event-driven model, you represent your application in feature-rich XUL components, and manipulate these components by listening to events triggered by users, as simple as you did for years in desktop applications. No JavaScript. No replication of business logic at the clients. No proprietary components. No compilation. ZK works with existent frameworks and technologies, such as JSF and Portals, so the pace of adapting it is all under your control.