The technology to ensure (sorta) real-time updates on your web app is called, COMET. This is a giant hack, basically. There are three common ways to actually implement it. Polling, Long Polling and Continuous connection, by using the forever frame pattern/trick.
The latest release includes seven new components, framework and bridge enhancements, support for JSR-168 Portlets as well as improved support for Spring Web Flow and JBoss Seam.
Today's clients want and have begun to expect desktop features in browser-based applications. RichFaces is one of a new breed of user interface component suites available for Java™ Server Faces (JSF). Among other benefits, RichFaces provides built-in JavaScript and Ajax capabilities to meet those expectations.