Can I run two tomcat instances on the same machine?

Apart from changing Connector port for protocol="HTTP/1.1" described in one of the answers below.

I think it requires to change Server port for ‘Shutdown’

<Server port="8005" shutdown="SHUTDOWN">

and also AJP port no.

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

If you want to run multiple tomcat instances in parallel.