There are a ton of AJAX libraries out there, which is not surprising. It seems like one of the most common ones for Java apps is DWR. I considered using it, but I have some “philosophical” issues with it. I really hate scriptlets inside JSPs. I think this comes from bad experiences with such JSPs early on in my career. I’ve also had to deal with some really bad programmers who thought that the only way to program in Java was to do it in a scriptlet on a JSP page. So the idea of using DWR to directly invoke a business method just seems like a step backwards.