Defining the application and its event handlers in Application.cfc

The Application.cfc file defines application-wide settings and variables, and application event handlers:

Application-wide settings and variables include page processing settings, default variables, data sources, style settings, and other application-level constants.
Application event handlers are CFC methods that ColdFusion MX automatically executes when specific events occur during the lifetime of an application: application start and end, session start and end, request start, execution, and end, and exceptions.