concept configuration file in category java

This is an excerpt from Manning's book Spring Roo in Action.
TilesViewResolver processes view names, emitted in the controller, and attempts to find layout definitions within configuration files specified in the definitions property. The main layout definitions file, layouts.xml, is what tells Roo about the two main layouts—default and public, as shown in the following listing.
Security commands aren’t available until you install the web components of a Roo application. After you’ve typed in the controller command, the Roo framework will generate the controller classes and configuration files. Now you’re ready to install and configure the security API in the Roo application.