I discovered today that it is real easy to have something minor wrong in XML, and got a Command Not Handled Exception.
I was going through the exercise of creating a new managed bean for an upcoming project. I was working through Russ Maher's master class from IBM Connect 2013. The links to all the xpages presentations have recently been posted here. I had previously reviewed the slides, but now the video is available! What is cool, is that as I work through the presentation, I am actually coding for my new project. You can't pause a live presentation, like you can the video.
When I copied existing XML from another faces-config, I somehow made a syntax mistake, and got the "Command Not Handled Exception" as a result. To figure out what is wrong, you need to look on the server in the "data/IBM_TECHNICAL_SUPPORT" folder and see the stack trace for the unhandled exception.
I had thought the issue was that I was using 9.0 and the development server was 8.5.3, but it had nothing to do with that. I guess another reason to hate XML. I am glad that JSON is eclipsing the use of XML these days. Of course, XML will likely be around in some form forever.