Application Module Files
Four main files control the behavior of the application module.
<AppMod>.xml: The metadata file that contains all the definitions for every object included in the module. It includes all the attribute definitions needed during design time for all the view objects and view links in the module. This is the file that you edit declaratively when editing the application module.
bc4j.xcfg: Contains all the configuration information including the JDeveloper connection details. This file is used by the Tester while running the module. You edit this file declaratively by using project properties (Business Components) to edit connection details, and by right-clicking the application module and selecting Configurations to edit configuration details.
<AppMod>Impl.java: Contains all the methods and behaviors for the application module for which you have defined code. You need to generate this file only if you have to programmatically modify the behavior of the application module.
<AppMod>Def.java: The application module definition class. At run time, one application module definition is instantiated for each application module. You can add methods to this class that are used by all instances, but this file is not used as often as <AppMod>Impl.java.