Is it possible run XWiki as a Windows Service??

XWiki is just a web application that runs in a Servlet Container. Thus, "running XWiki as a Windows Service" means running the Container as a Windows Service.

Almost all Servlet Containers support running as a Service. 

Here are some tools that can run any Java application as a Service:

• Java Service Wrapper
• Apache Daemon ProcRun

And here are some links to run a specific container as a Service:

• Jetty 7 and also the Jetty Windows Service Wrapper
• Tomcat 7

For how to install XWiki into a Servlet Container, see the WAR Installation Guide.