Hand Coding: If you have an ADF component with a custom Java class and later decide to base the component on a framework extension class, click the Class Extends button on the Java page of the component editor to change the component’s base class. This updates the component’s XML component definition to reflect the new base class and also modifies the EXTENDS clause in the component’s custom Java class. If you manually update the EXTENDS clause without using the component editor, the component’s XML component definition does not reflect the new inheritance and, the next time you open the editor, your manually modified EXTENDS clause will be overwritten with what the component editor believes is the correct component base class.
Multiple Levels: In the examples in the slide, you see a single CustomAppModuleImpl class that extends the base ApplicationModuleImpl class. However, there is no fixed limit on how many levels of framework extension classes you create.
Preferences: If you decide to use a specific set of framework extension classes as the standard for a given project, you can open the Business Components > Base Classes page in the Project Properties dialog box to define your preferred base classes for each component type.