You can setup Tomcat so that it will listen on multiple ports, without having to setup 2 instances, simply edit the conf/server.xml configuration file and add a new connector for the port you want. For example if you have a connector like that:

<Connector port="80" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" URIEncoding="UTF-8" /> 

Add this to that file as well:

<Connector port="8000" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" URIEncoding="UTF-8" /> 

Make sure it's redirected to the appropriate location.

References

• Running Tomcat server on two different portsRunning Tomcat server on two different ports