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

SAP Error Message - Details

• 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 implemented all the necessary methods or properties required by CL_SHM_AREA.
  
  Solution:
  
  
  Check Class Definition: Ensure that the class you are using as the area class correctly inherits from CL_SHM_AREA. The class definition should look something like this:
  CLASS your_class_name DEFINITION
    INHERITING FROM cl_shm_area
    ...
  ENDCLASS.
  
  
  Activate the Class: If you have recently created or modified the class, make sure it is activated in the ABAP Workbench (SE80 or SE11).
  
  
  Review Implementation: Ensure that the class implements all required methods and properties as defined in CL_SHM_AREA. This includes methods for managing the lifecycle of the shared memory area.
  
  
  Check for Typos: Verify that there are no typographical errors in the class name or in the way it is referenced in your code.
  
  
  Namespace and Accessibility: Ensure that the class is in the correct namespace and is accessible from the context where you are trying to use it.
  
  
  Debugging: If the issue persists, consider debugging the code to trace where the error is being raised and to inspect the class being used.
  
  
  Related Information:
  
  Documentation: Refer to the SAP documentation for CL_SHM_AREA to understand the requirements and methods that need to be implemented.
  SAP Notes: Check for any relevant SAP Notes that might address known issues or provide additional guidance on using shared memory areas.
  Community Forums: Consider searching or posting on SAP community forums (like SAP Community or Stack Overflow) for additional insights from other developers who may have encountered similar issues.
  
  By following these steps, you should be able to resolve the SHMA021 error and successfully use shared memory areas in your SAP application.