How To Fix WES_OUTBOUND028 - Class &1 is not &2 or its subordinate class

SAP Error Message - Details

• Message type: E = Error

• Message class: WES_OUTBOUND - Messages for Outbound Services

• Message number: 028

• Message text: Class &1 is not &2 or its subordinate class

Self-Explanatory Message

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• What is the cause and solution for SAP error message WES_OUTBOUND028 - Class &1 is not &2 or its subordinate class ?

  SAP Error Message:
  
  WES_OUTBOUND028 Class &1 is not &2 or its subordinate class
  
  Cause:
  This error occurs in SAP when the system expects an object of a certain class or one of its subclasses, but the actual object passed or processed is of a different class that does not match the expected class hierarchy.
  In other words, the system is performing a type check and finds that the class of the object (&1) is not the expected class (&2) nor a subclass (subordinate class) of it. This typically happens in object-oriented ABAP programming or in scenarios involving Business Object Repository (BOR) objects, where strict type compatibility is required.
  
  When does it occur?
  
  During outbound processing in SAP Workflow or Business Object processing.
  When a method or function module expects an instance of a particular class or subclass, but receives an incompatible object.
  In ALE/IDoc processing or integration scenarios where object types are validated.
  In custom developments or enhancements involving polymorphism or class inheritance.
  
  
  Solution:
  
  
  Check the Class Hierarchy:
  
  Verify the class of the object being passed (&1).
  Check if this class is indeed the expected class (&2) or a subclass of it.
  Use transaction SE24 (Class Builder) to inspect the class hierarchy.
  
  
  
  Correct the Object Instantiation:
  
  Ensure that the object being instantiated or passed is of the correct class or a subclass.
  If a wrong class is instantiated, modify the code to instantiate the correct class.
  
  
  
  Adjust the Method Parameters:
  
  If the method signature expects a certain class, ensure that the calling code complies.
  If polymorphism is intended, make sure the class inheritance is properly defined.
  
  
  
  Review Custom Code or Enhancements:
  
  If this error arises in custom code, debug to find where the object is created or passed.
  Fix the code to pass the correct object type.
  
  
  
  Check Business Object Repository (BOR) Objects:
  
  If the error is related to BOR objects, verify the object types and their inheritance in transaction SWO1.
  
  
  
  Consult SAP Notes:
  
  Search for SAP Notes related to WES_OUTBOUND028 for any known issues or patches.
  
  
  
  
  Related Information:
  
  
  Transaction Codes:
  
  SE24 - Class Builder (to check class definitions and inheritance)
  SWO1 - Business Object Builder (to check BOR objects)
  SE80 - Object Navigator (to browse programs, classes, and objects)
  
  
  
  ABAP Concepts:
  
  Class inheritance and polymorphism
  Type checking with IS INSTANCE OF or CASTING
  Exception handling in object-oriented ABAP
  
  
  
  Typical ABAP Code Snippet Causing This:
  DATA: obj TYPE REF TO cl_expected_class.
  obj = cl_wrong_class=>create( ). " This will cause the error if cl_wrong_class is not subclass of cl_expected_class
  
  
  Debugging Tips:
  
  Set breakpoints where the object is created or passed.
  Check the runtime type of the object using RTTI or DESCRIBE OBJECT.
  
  
  
  
  Summary:
  The error WES_OUTBOUND028 Class &1 is not &2 or its subordinate class indicates a type mismatch in class inheritance. The solution is to ensure that the object involved is of the expected class or a subclass, by verifying and correcting the class hierarchy and object instantiation in the relevant code or configuration.
  
  If you provide the context or the code snippet where this error occurs, I can help you with a more specific solution.