How To Fix OO021 - Interface &1 still contained in interface &2

OO021 - Overview

• Message type: E = Error

• Message class: OO - Class Builder/API

• Message number: 021

• Message text: Interface &1 still contained in interface &2

What causes this issue?

You wanted to delete the implementation relationship for interface
&V1&. However, interface &V1& is still implemented in interface &V2&.
Since all interfaces contained in &V2& must be implemented, you cannot
delete the implementation relationship for &V1& unless the
implementation relationship for &V2& is also deleted.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message OO021 - Interface &1 still contained in interface &2 ?

  The SAP error message OO021 indicates that there is an issue with the interface implementation in ABAP (Advanced Business Application Programming). Specifically, it means that an interface (let's call it &1) is still referenced or contained within another interface (&2), which is causing a conflict or violation of the interface implementation rules.
  
  Cause:
  
  
  Interface Inheritance: The error typically arises when an interface that is supposed to be removed or modified is still being referenced by another interface. This can happen if:
  
  The interface is still being used in the implementation of another interface.
  There are dependencies that have not been resolved.
  The interface has not been properly detached from the implementing classes or other interfaces.
  
  
  
  Implementation Issues: If you are trying to delete or modify an interface that is still in use, the system will prevent this action to maintain data integrity and consistency.
  
  
  
  Solution:
  
  
  Check Dependencies: 
  
  Use transaction SE80 (Object Navigator) or SE11 (Data Dictionary) to check