From the IBM website:

The page-reload cycle presents one of the biggest usability obstacles in Web application development and is a serious challenge for Java™ developers. In this series, author Philip McCarthy introduces a groundbreaking approach to creating dynamic Web application experiences. Ajax (Asynchronous JavaScript and XML) is a programming technique that lets you combine Java technologies, XML, and JavaScript for Java-based Web applications that break the page-reload paradigm.

Nothing like a framework to ease your burden.  Check it out, more than 50 java development frameworks are described and linked.  Of course the usual suspects are here: Cocoon, Struts, and Java Server Faces.  But also includes Tapestry, RSF, ZK and JAT.  Wow, glad we are finally moving into this space...