Component taxonomy

Tomcat's architecture follows the construction of a Matrushka doll from Russia. In other words, it is all about containment where one entity contains another, and that entity in turn contains yet another.

In Tomcat, a 'container' is a generic term that refers to any component that can contain another, such as a Server, Service, Engine, Host, or Context.

Of these, the Server and Service components are special containers, designated as Top Level Elements as they represent aspects of the running Tomcat instance. All the other Tomcat components are subordinate to these top level elements.

The Engine, Host, and Context components are officially termed Containers, and refer to components that process incoming requests and generate an appropriate outgoing response.

Nested Components can be thought of as sub-elements that can be nested inside either Top Level Elements or other Containers to configure how they function. Examples of nested components include the Valve...