This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
I would guess that IIS is the only server capable of running .Net applications (unless Mono can do that...?).
But you may be able to run Java web apps on the same machine as IIS (or even in-process with IIS) using something like NewAtlanta ServletExec or Tomcat's JK ISAPI plugin. That would allow some degree of integration.