You write code in the CUSTOM library, within the procedure shells that are provided. All logic must branch based on the form and block for which you want it to run. Oracle Applications sends events to the CUSTOM library. Your custom code can take effect based on these events.
Attention: The CUSTOM library is provided for the exclusive use of Oracle Applications customers. The Oracle Applications products do not supply any predefined logic in the CUSTOM library other than the procedure shells described here.
See: Writing Code for the CUSTOM Library
When to Use the CUSTOM Library
CUSTOM Library Package Procedures
Support and Upgrading
Example of Implementing Zoom Using the CUSTOM Library