NOTE
Tomcat Lifecycle
Tomcat component lifecycle initialization, start, stop, destroy, and lifecycle events.
This is a historical learning note and may contain outdated or incomplete understanding.
Tomcat components participate in a managed lifecycle with states/transitions such as initialization, start, stop, and destruction.
The lifecycle abstraction lets parent components coordinate children and lets listeners react to transitions without every component hard-coding startup dependencies.
When reading Tomcat source, lifecycle state is often more informative than memorizing one method call order, because classes and implementation details change between releases.