How To Fix DMU158 - Class &1 with class type &2 is not a subclass of &3

SAP Error Message - Details

• Message type: E = Error

• Message class: DMU - Digital Mock Up (DMU)

• Message number: 158

• Message text: Class &1 with class type &2 is not a subclass of &3

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

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Smart SAP Assistant

• What is the cause and solution for SAP error message DMU158 - Class &1 with class type &2 is not a subclass of &3 ?

  The SAP error message DMU158 indicates that there is an issue with class inheritance in the context of the Data Migration Workbench (DMW) or similar object-oriented programming scenarios in SAP. Specifically, the error message states that a class (denoted as &1) with a certain class type (denoted as &2) is not a subclass of another specified class (denoted as &3). 
  Cause:
  
  Class Hierarchy Issue: The class you are trying to use is not correctly defined as a subclass of the expected parent class. This could be due to incorrect class definitions or misconfigurations in the class hierarchy.
  Incorrect Class Type: The class type specified may not be compatible with the expected class type. For example, you might be trying to use a class that is not intended to inherit from the specified parent class.
  Transport Issues: If the class was recently transported from another system, there may be inconsistencies in the class definitions or missing dependencies.
  
  Solution:
  
  
  Check Class Definition: Verify the class definition in the SAP system. Ensure that the class you are trying to use is indeed a subclass of the specified parent class. You can do this by navigating to the class in the Class Builder (transaction code SE24) and checking its inheritance.
  
  
  Adjust Class Hierarchy: If the class is not a subclass of the expected parent class, you may need to adjust the class hierarchy. This could involve modifying the class definition to inherit from the correct parent class.
  
  
  Review Class Type: Ensure that the class type (e.g., ABAP class, interface, etc.) is appropriate for the context in which it is being used. If necessary, create a new class that correctly inherits from the desired parent class.
  
  
  Check Transport Requests: If the class was recently transported, check the transport requests for any missing objects or dependencies. Ensure that all related classes and interfaces are present in the target system.
  
  
  Consult Documentation: Review any relevant SAP documentation or notes related to the specific classes and their intended use. This can provide insights into proper class usage and inheritance.
  
  
  Debugging: If the issue persists, consider debugging the program or transaction that is triggering the error to gain more context on where the problem lies.
  
  
  Related Information:
  
  Transaction Codes: Use SE24 (Class Builder) to view and edit class definitions, and SE80 (Object Navigator) for a broader view of objects.
  SAP Notes: Check SAP Notes for any known issues or patches related to class inheritance and the specific error message.
  Community Forums: Engage with SAP community forums or support channels for additional insights and solutions from other users who may have encountered similar issues.
  
  By following these steps, you should be able to identify and resolve the cause of the DMU158 error message in your SAP environment.