The first thing I do when I encounter an issue like this is to see if the project in question has been re-homed. Meaning that a more up-to-date version lives under a different website/package tree.
Unfortunately, there's nothing for DWR. In fact, the DWR homepage itself is no longer online. That counts as unsupported technology to me. Often a technology becomes unsupported because a better alternative has come along.
A quick check seems to indicate that jQuery plus a JSON library would be one alternative (which, incidentally, I've used without ever knowing of DWR). Note that if you're using JavaServer Faces, jQuery is already inside, although you may wish to override the default version, which tends to be fairly old.
Wholesale shuttling of
Java objects between client and server for its own sake is something I don't encourage. It lends itself to easy hacking, so I'd be limiting the properties being transmitted to only what is essential.
One source recommended YAML. I'm a big YAML fan because of all the popular web service data formats (XML, JSON and YAML), it's the easiest to type, and like XML and JSON, you can source it from a
JSP template. But I'm not sure I'd prefer it to JSON when used with AJAX or in JavaScript in general.