Customizable app loading message

Hi all. When I start up my rails app in Glassfish or Tomcat, the
appserver
starts to serve requests almost immediately even though the app isn’t
loaded. In Tomcat, you get a blank page. In Glassfish, you get a page
that
says your app is loading. I’ve seen other Java based apps where you can
provide a custom “loading” page (Hudson is one of them). Does anyone
know
if there’s a way to do this in a standard way? If not, sounds like a
worthy
enhancement request for JRuby-Rack.
Actually, I’d prefer that Glassfish/Tomcat don’t start serving requests
until the apps are loaded. This allows the load balancer to do its job.
However, if this isn’t possible it would be nice to allow for a custom
loading page rather than the dreaded blank page that Tomcat spits out.

Rich