What are main configuration files of Tomcat ?

Tomcat's configuration is based on two files :

server.xml 

Tomcat's global configuration file.

It serves two goals :

  1. Providing initial configuration for the Tomcat components.

  2. Specifying structure for Tomcat, meaning, letting Tomcat boot and build itself by instantiating components as specified in server.xml.

web.xml

Configures the various contexts in Tomcat.

Tomcat lets the user define default web.xml values for all context by putting adefault web.xml file in the conf directory.

When constructing a new Context, Tomcat uses the default web.xml file as the base configuration and the application specific web.xml

(the one located in the application's WEB-INF/web.xml), only overwrite these defaults.