I have a couple of comments/criticisms on this article.

The first is that the ajaxFunctions Java class doesn't follow the standard Java naming conventions for a class. I believe this was done to make it look more natural in the html pages, but I think when deviating from a well known standard it's good to briefly state why.

The second is that the ajaxFunctions class is essentially a Facade over other functionality, but the author never really states that or recommends using a Facade pattern instead of directly accessing beans or a DAO layer.

The third comment I have is that DWR seems to require putting HTML back into our java code. One of the nice things aboutJSP rendering is that you don't have a bunch of println or string concatenations to build the HTML code directly in your servlet class. It's seems a step backwards to start putting HTML rendering in our Java code. It would have been nice to touch upon this. It's an obvious drawback or at least something that will make many people pause before try DWR. Other AJAX libraries allow you to make use of Java's JSP rendering to format and return HTML content.

Putting AJAX functionality into your Web application can be a daunting task when you're first learning AJAX. After all you're a Java programmer not a JavaScript programmer. It can also be very frustrating having to learn how the different browsers handle XMLHttpRequests. It's been reported, however, that Internet Explorer 7 will support native XMLHttpRequests rather than requiring the developer to make ActiveX requests. This will make a Web developer's life a lot easier.