How To Fix OO004 - Class &1 has an invalid multiple inheritance

SAP Error Message - Details

• Message type: E = Error

• Message class: OO - Class Builder/API

• Message number: 004

• Message text: Class &1 has an invalid multiple inheritance

What causes this issue?

More than one inheritance relationship is defined for class &1. The
class can no longer be edited.

How to fix this error?

Run a clean-up for the data.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message OO004 - Class &1 has an invalid multiple inheritance ?

  The SAP error message OO004, which states "Class &1 has an invalid multiple inheritance," typically occurs in the context of ABAP Object-Oriented programming when there is an issue with the inheritance structure of classes. This error indicates that the class in question is attempting to inherit from multiple classes in a way that is not allowed by the rules of the ABAP Object-Oriented programming model.
  Cause:
  
  Multiple Inheritance: ABAP does not support multiple inheritance in the same way that some other object-oriented languages do. If a class tries to inherit from more than one superclass that has a common ancestor, it can lead to ambiguity and conflicts.
  Circular References: If the inheritance structure creates a circular reference, it can also trigger this error.
  Incorrect Class Definition: The class might be defined incorrectly, or there may be a misconfiguration in the class hierarchy.
  
  Solution:
  
  Review Class Hierarchy: Check the inheritance structure of the class that is causing the error. Ensure that it does not inherit from multiple classes that could lead to ambiguity.
  Refactor Code: If multiple inheritance is necessary for your design, consider refactoring your code. You can use interfaces to achieve similar functionality without violating the single inheritance rule.
  Check for Circular References: Ensure that there are no circular references in the class hierarchy.
  Use Composition: Instead of inheritance, consider using composition, where a class contains instances of other classes rather than inheriting from them.
  Consult Documentation: Refer to the SAP documentation for guidelines on class design and inheritance rules in ABAP.
  
  Related Information:
  
  ABAP Object-Oriented Programming: Understanding the principles of object-oriented programming in ABAP is crucial. Familiarize yourself with concepts like classes, interfaces, inheritance, and polymorphism.
  SAP Notes and Community: Check SAP Notes for any specific patches or updates related to this error. The SAP Community forums can also be a valuable resource for finding solutions to similar issues encountered by other developers.
  Best Practices: Follow best practices for class design in ABAP, such as keeping class hierarchies simple and avoiding deep inheritance trees.
  
  By addressing the issues outlined above, you should be able to resolve the OO004 error and ensure that your class definitions comply with ABAP's object-oriented programming rules.