What is the use of adding an exception to a method of a global class?

Question

So, I added this image, hoping it would help :

My question is: What is the point of doing this? I have created my global exception class(with my own messages), I have raised it in a method of a global class and I have also caught this exception - and I have done all these without giving that particular method the exception, so does it help in any way to give a method exceptions?

Short update, this is my method code:

A coworker told me to give the method an exception parameter instead of writing the code from picture 2. If I do so, I don't see any changes and this is why I do not see the point of doing what is in the first picture.

Answer 1

This is a very good question. Because of the overhead, such exceptions create either by creating them, adding them, linking them to a message-class and throwing/catching them, it really, also for me, seems sometimes a kind of "shooting rockets at birds". Most things can really be caught by catching CX_ROOT. Nevertheless there are really cases, where it is important to distinguish between exceptions, and therefore it is a nice-oop-standard to create some own, If:

• the exception's class type/meaning cannot be covered by the abap-standard exceptions
• the exception class should be linked against own message-class-messages
• the exception class should provide special features like "resumable".

In the end this question is some kind of "best practice/best usecase" question and I also would be glad to see some other answers, which can pinpoint to other points of view about this topic.