Probably because you're using Eclipse. WIth the
WTP
J2EE plugin that comes in the Eclipse J2EE spin. Which does rude things to the Tomcat configuration.
Tomcat should be producing logs, and if the webapp is deployed, one of the things that should be IN those logs are messages that indicate what webapps are being deployed as Tomcat starts up. An empty log means that you've probably not appeased the Eclipse WTP plugin.