Hi Willi
I get what you are saying and sure, the SAP notes application / principal is nice.
The JAVA side also does some checks, you cannot just downgrade a component there without additional efforts.
Downloading the JAVA patches is possible through SAP Solution Manager maintenance optimizer and SAP Service Marketplace maintenance planner application (given you've got everything set up) in combination with Download Basket.
So while there are differences, it's similar to some extent as well. It's a different technology stack though so it has different implications / impact anyway.
I can definitely agree that applying bug fix patches on the ABAP side using SAP notes is more pleasant 
.
Best regards
Tom