Normally, each context in server.xml file has a corresponding directory under
webapps, and vice versa. However, when I deployed a app under webapps directory with the help of the
manager app, I noticed that there is no change to server.xml. When I restarted
the server, the newly deployed app is picked up and become accessible as normal.
Looks like as long as the app directory is there, it does not matter much wether
the context is in the server.xml file or not.

My question is that is it true that Tomcat looks for deployed apps/contexts
under webapps directory and server.xml only provides additional information for
the apps/contexts?

An brief explanation on the relationship between these two entities will be
greatly appreciated.

Thanks!