'The collaborative efforts of the Liferay and ICEfaces development teams have addressed the complexities of incorporating JSF and Ajax in Portals, allowing the developer to focus on the creative aspects of rich portal development
Metawidget, the library that lets you generate a user interface from your domain objects,the Java Server Faces (JSF) Metawidget now supports the popular Facelets framework.
There's a refrence in the article to using metawidget with 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.