DWR (Direct Web Remoting)

JSON-RPC-Java vs. DWR
JSFのカスタムコンポーネントを作ってまして、それに丁度Ajax的な機能が必要かなーってのでのぞいたのがこの２つ。

JSON-RPC-Java以外にもあるんですな。

DWR (Direct Web Remoting)What DWR does for you:
DWR gives you a very easy way to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code. So you don't need to create servlets and web.xml entries for all your code, you don't need struts config files or JSF magic incantations, no writing Actions or implementing some special interface. Just you, DWR, Java, HTML and Javascript.
DWR gives you a jump-start to being able to create GMail type interactivity. We are gradually moving to a web where more and more is done dynamically, and love it or lothe it that means Javascript. DWR makes the Javascript easier by giving you a set of examples of how to create dynamic sites.

ざーっと見てみたんだけど、web.xml、dwr.xmlの設定が多いっす。でもJavaScript側のコードは結構シンプルで良いかも。