Hi guys, apologies for the delay in filing this, life has been chaotic recently. I've spent the last couple of days working through this issue with ResourceMapping in 3.0.0.M3. As it turns out, the ResourceServlet is getting configured and added properly, but the context that it is added to is never started.
The Blueprint configuration I am using and which works in Pax Web 2.1.0 is the following:
When a request is made for a resource that has been added in this manner, the call chain makes it's way to org.eclipse.jetty.server.handler.ContextHandler#checkContext, which starts by looking at _availability. In my case, this is always set to __STOPPED. No error is generated on the console and a "Not found" screen is returned. One would presume from this that the context is not started yet, but it's not clear who or what starts it since I'm not familiar enough (yet) to find what changed.
More as I get it!