I am using Apache Tomcat 6.0.18 on a Windows Server that also has IIS.
For IIS I can enable Integrated Windows authentication to fetch the
Intranet Windows login username using ColdFusion.

Is there a setting in Apache Tomcat I need to enable Integrated Windows authentication so I can fetch the Intranet Windows login username using JSP?

For Server side ColdFusion (using IIS) I use the CGI.AUTH_USER variable and it fetches the Intranet username.
For JSP (using Apache Tomcat) I tried this to fetch the username:
System.getenv("USERNAME")
It output SYSTEM instead of my username.

I assume if I can fetch Intranet Windows login username with a server side like ColdFusion I can also do it with JSP since they are both on the same Web server except ColdFusion uses IIS and JSP is sitting on Tomcat.
Please advise.