Learn how can you create a simple web service in few minutes.
This exercise consist of exposing a Function Group as a Enterprise service which is ready to be consumed by a consumer web service.
This Articles contains the Example with explanation which will help you to understand Function module EXIT and how to work with it.
Check this article to know how SCREEN EXIT works.It also contains the example of SCREEN EXIT with screen shots.
Check this beautiful article to know everything about USEREXIT. It also contains tutorial of how to implement a User EXIT.
Read this article to know what are the different ways using which you can Enhance Standard SAP as per your requirement
