Best server-side framework for heavy AJAX Java application

Question

There are zillions of Java web application frameworks.

95% were designed before the modern era of AJAX/DHTML-based development, and that means these new methods are

Answer 1

Echo2 / Echo3 by Nextapp (www.nextapp.com) is totally awesome.

Advantages over GWT:

1) It is not limited to a sub-set of java like GWT 2) It is easier (in my estimation) to learn 3) Has extremely robust design studio for almost drag and drop designing.
4) It is very fast, and works very well on all platforms browsers 5) You can write your application using either java script or java 6) It has great and straight forward methods for handling events and actions.

Personally I think that for any web-application in which you are trying to integrate java and speedy delivery I wouldn't hesitate to pick Echo3 or Echo2.