How To Fix SHMA021 - & is not a valid area class (does not inherit from CL_SHM_AREA).

SHMA021 - Overview

• Message type: E = Error

• Message class: SHMA - Shared Objects: Management Messages

• Message number: 021

• Message text: & is not a valid area class (does not inherit from CL_SHM_AREA).

What causes this issue?

In this transaction you may only process classes that belong to the
areas for shared objects. These classes are thus marked in such a way
that they are derived from the class CL_SHM_AREA.

System Response

Error message. The required processing cannot be executed.

How to fix this error?

Edit the class in the Class Builder (transaction SE24) or enter a valid
area class.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message SHMA021 - & is not a valid area class (does not inherit from CL_SHM_AREA). ?

  The SAP error message SHMA021 indicates that there is an issue with the area class being used in the context of SAP's Shared Memory (SHM) framework. Specifically, the error states that the area class is not valid because it does not inherit from the base class CL_SHM_AREA. This typically occurs when you are trying to create or access a shared memory area with a class that does not conform to the required structure.
  
  Cause:
  
  Incorrect Class Definition: The class you are trying to use as an area class does not extend CL_SHM_AREA. This is a requirement for any class that is intended to be used as a shared memory area.
  Typographical Errors: There may be a typo in the class name or the class might not be activated.
  Namespace Issues: The class might be in a different namespace or package that is not accessible in the current context.
  Missing Implementation: The class might not have