jabsorb is a simple and lightweight Ajax/Web 2.0 framework that allows you to call methods in a Java web application from JavaScript code running in a web browser as if they were local objects residing directly in the browser.
jabsorb handles all the details of marshalling and unmarshalling objects back and forth between the client and server so that you can focus on writing your application features.
jabsorb makes use of the JSON-RPC protocol for it's transport mechanism. JSON-RPC is a standard protocol and jabsorb can interoperate with other standard JSON-RPC clients and servers that may be written in other languages.
Starting with jabsorb 1.2, additional ORB functionality has been added, and it extends the basic JSON-RPC protocol to allow for passing data structures that contain Circular References.
Direct Web Remoting
DWR allows Javascript in a browser to interact with Java on a server and helps you manipulate web pages with the results.
DWR is Easy Ajax for Java
Qwicket is a quickstart application for the wicket framework. Its intent is to provide a rapid method for creating a new wicket project with the basic infrastructure in place so that you can quickly get to the meat of your application rather than mucking with the plumbing of a wicket application. Currently, the system only supports spring and hibernate built with ant. Future plans include support for maven 2 and other persistence layers such as ibatis.