In any JEE production server machine, you will often find Apache and then the JEE server.
This is mostly because Apache is used as a reverse proxy and as a virtual host to filter what domain name goes where.

But now! With Tomcat 7's virtual host feature, I question the need for an Apache front anymore.
Tomcat can on it's own determine what app a request should go based on domain names. e.g foo.com , bar.com can both point to the same DNS IP address, fully manned by tomcat, and tomcat can forward these to whatever app it has been configured to run each domain as.

So why do folks still stick Apache in front of their Tomcat servers?
Seems like an unneccessary middle man now. Reasons?

Security !!
In linux you can turn on SELinux for many httpd services