How To Fix OO057 - A class cannot inherit from itself

SAP Error Message - Details

• Message type: E = Error

• Message class: OO - Class Builder/API

• Message number: 057

• Message text: A class cannot inherit from itself

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message OO057 - A class cannot inherit from itself ?

  The SAP error message OO057, which states "A class cannot inherit from itself," typically occurs in the context of ABAP Object-Oriented programming when there is an attempt to define a class that inherits from itself, either directly or indirectly. This is not allowed in object-oriented programming as it creates a circular reference that cannot be resolved.
  Cause:
  
  Direct Self-Inheritance: The class is defined to inherit from itself.
  Indirect Self-Inheritance: There is a chain of inheritance where a class inherits from another class, which in turn inherits from the original class, creating a loop.
  Typographical Error: A typo in the class name or incorrect reference in the inheritance declaration.
  
  Solution:
  
  
  Check Class Definition: Review the class definition to ensure that it does not directly inherit from itself. For example, if you have:
  CLASS my_class DEFINITION INHERITING FROM my_class.
  This should be corrected.
  
  
  Review Inheritance Chain: If the class inherits from another class, check that the parent class does not eventually lead back to the original class. You can do this by tracing the inheritance hierarchy.
  
  
  Correct Typographical Errors: Ensure that the class names are correctly spelled and that you are not mistakenly referencing the same class.
  
  
  Refactor Code: If you find that the design requires a class to inherit from itself (which is not possible), consider refactoring the code to eliminate the circular dependency. This might involve redesigning the class structure or using interfaces.
  
  
  Related Information:
  
  ABAP Documentation: Refer to the official SAP documentation for guidelines on class definitions and inheritance.
  Object-Oriented Programming Principles: Understanding the principles of inheritance and polymorphism can help avoid such issues in the future.
  Debugging Tools: Use the ABAP Workbench tools to analyze class definitions and their relationships to identify where the circular reference occurs.
  
  By following these steps, you should be able to resolve the OO057 error and ensure that your class definitions adhere to the rules of object-oriented programming in ABAP.