There's a one-to-one correspondence between the Direct to Java Client D2WComponent subclasses and the client side EOControllers. For example, on the client side, there's an EOTextFieldController. The corresponding server side D2WComponent class is also named EOTextFieldController. The client side class creates and manages user interface widgets, while the server side class generates XML to describe how to configure the client side controller.
The Direct to Java Client D2WComponents have .wos with .html and .wod files, which you can see in the DirectToJavaClient framework.
Navigate to the DirectToJavaClient framework (in /System/Library/Frameworks on Mac OS X Server or in $NEXT_ROOT/Library/Frameworks on Windows).
Navigate to the Resources folder.
In the Resources folder you can see the .wo files for all the Direct to Java Client D2WComponents.
Double-click the EOBoxController.wo to open it in WebObjects Builder.
The EOBoxController.html contains XML instead of the typical HTML, so WebObjects Builder must open the component in source view mode.
