In talking about deployment of web applications, the concept of a
Context is required to be understood. A Context is what Tomcat
calls a web application.
In order to configure a Context within Tomcat a Context Descriptor
is required. A Context Descriptor is simply an XML file that contains
Tomcat related configuration for a Context, e.g naming resources or
session manager configuration. In earlier versions of
Tomcat the content of a Context Descriptor configuration was often stored within
Tomcat's primary configuration file server.xml but this is now
discouraged (although it currently still works).
Context Descriptors not only help Tomcat to know how to configure
Contexts but other tools such as the Tomcat Manager and TCD often use
these Context Descriptors to perform their roles properly.
The locations for Context Descriptors are:
Files in (1) are named [webappname].xml but files in (2) are named
context.xml. If a Context Descriptor is not provided for a Context,
Tomcat configures the Context using default values.