An AJAX framework that leverages widgets from existing and
future AJAX toolkits and frameworks, for example, Dojo,
Scriptaculus, Yahoo UI Widgets and DHTML Goodies.

• JavaScript Wrapper framework for the Java platform;
• Allows developers to take widgets from many popular AJAX
  toolkits and frameworks, and wrap them into a JSP or JSF tag;
• Provides a common programming model to developers;

A nice overview of AJAX and jMaki: http://www.javapassion.com/ajax/AJAXFrameworks.pdf

GWT: http://www.javapassion.com/ajax/GWT.pdf

jMaki: http://www.javapassion.com/ajax/jMaki.pdf

Sample jMaki widgets and other third party widgets: http://nora.lis.uiuc.edu:9090/jmaki/

Code sample:

<%@ taglib prefix="a" uri="http://java.sun.com/jmaki" %>

Since there's only a limited set of HTML tags supported by
OpenLaszlo:

http://www.openlaszlo.org/lps-latest/docs/reference/index.html

it might be easier to use jMaki in JSP or DHTML applications.

XHR: on success, on failure, pause an xhr and come back to it later:

?

Timer/Timeout:

Yes. https://ajax.dev.java.net/glue.html

History/state (back button):

Yes.

Off-line Storage:

?

Interaction with the Desktop applications:

No.

Extensibility:

Very good. It's designed for this purpose (e.g. Prototype, dojo).

Animation:

Yes, via. javascript.

Number of Items that can be displayed in the interface without causing memory or computation problems.

?

Support for stateless messaging? -scalability:

Yes.

Usability? Bookmarking/Layout font-size changes:

Yes.

Browser Portability:

Very good.

Start Time? How big are the javascripts/swf files....

Reportedly much faster than Ajax4JSF. Relatively small.

TESTING and Debugging tools. How can you test the GUI interface? GWTTestCase

Firebug plugin for client-side.
Also has NetBean IDE integration for development.

Will the generated HTML be portable and what happens when a new browser comes in?

Yes.

Remote Process Calls? Different from JSON and XML.

No.

Batch XML Http Requests?

No.