I don't think this has nothing to do with JBoss serving blank pages. If your app is not available, how is JBoss going to know what to serve the request?

To do what you want with a simple webapp setup, you can try is this:

1. Create an static html page in your ROOT.war/your-webapp-name/index.html

2. Deploy your webapp with same name as <your-webapp-name>.war

With this, your default url access of http://localhost/your-webapp-name will load the static page at first, and as soon as your webapp is successfully loaded, it will overwrite that path.

to do so, edit web.xml in your server/xxx/deployers/jbossweb.deployer directory to add the following:

<error-page>
          <error-code>404</error-code>
          <location>/myerror.html</location>
</error-page>

myerroy.html is the customized page you want to display when app is not available. (myerror.html need to be larger than 512 bytes , otherwise some browsers would not load your customized error page)

then put the myerror.html to the root context app of your jboss instance, the default root context app is ROOT.war which is located in your server/xxx/deploy directory.