Ajax was easily the most talked about technology at JavaOne 2006. Java developers it seemed wanted to get into Ajax by any means possible. So there were 100s lined up for every session that had "Ajax" in its title. It does make sense for developers to try and pick up Ajax soon, as the Ajax hype will move beyond the tech community and you would soon see managers and customers demanding that their applications be Ajaxed. Irrespective of what you think of Ajax, you now have to be able to develop Ajax apps.

Understanding Ajax is one part of the issue however the more complex part is that of actually implementing it. As no real Java developer can develop an application without using a framework, it was only a matter of time before hundreds of Ajax frameworks sprang up. With frameworks, there's always the concern that you will lock your applications into the framework or even worse adopt a framework that isn't suited to your needs.

You also need to watch out for frameworks that claim Ajax enabled solely because they have included a popular Ajax Javascript framework in their distribution. Using readymade Ajax enabled JSF components is also a good option that needs to be considered.

Here I have listed a handful of frameworks that I thought will serve us well over the long run. The primary factors I relied on were 1) already established 2) promoted by a major player.

If you feel any other framework should have been on this list, do add a comment.

1) Google Web Toolkit - Build AJAX apps in the Java language: Google Web Toolkit (GWT) is a Java software development framework that makes writing AJAX applications like Google Maps and Gmail easy for developers who don't speak browser quirks as a second language.
http://code.google.com/webtoolkit/

2) Dojo: Dojo is an Open Source DHTML toolkit written in JavaScript. Dojo aims to solve some long-standing historical problems with DHTML which prevented mass adoption of dynamic web application development.
http://dojotoolkit.org/

3) Yahoo! User Interface Library: The Yahoo! User Interface (YUI) Library is a set of utilities and controls, written in JavaScript, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX.
http://developer.yahoo.com/yui/

4) 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.
http://getahead.ltd.uk/dwr/

5) Spry framework for Ajax: The Spry framework for Ajax is a JavaScript library for web designers that provides functionality that allows designers to build pages that provide a richer experience for their users. It is designed to bring Ajax to the web design community who can benefit from Ajax, but are not well served by other frameworks.
http://labs.adobe.com/technologies/spry/

6) Mochikit: MochiKit is a free lightweight JavaScript library.
http://mochikit.com/

7) Script.aculo.us: Provides you with easy-to-use, compatible and, ultimately, totally cool JavaScript libraries to make your web sites and web applications fly, Web 2.0 style.
http://script.aculo.us/

With Ajax, there's a difference between Javascript based client side frameworks and Java based server side frameworks. So you will also find several serverside frameworks that include one of the client side frameworks mentioned above.

It's time developers start getting their hands dirty trying out these frameworks and being Ajax ready!

- Harshad Oak

Related:
>> Is AJAX worth adopting?
>> Ajax technologies aren't particularly new or sexy
>> Rails has a huge lead on integrated Ajax development
>> New RAD platform to fill the J2EE-AJAX void
>> Webwork integrates with Dojo