How To Fix CL668 - Class type &1 does not allow additional objects

SAP Error Message - Details

• Message type: E = Error

• Message class: CL - Classification

• Message number: 668

• Message text: Class type &1 does not allow additional objects

What causes this issue?

Class type &V1& does not have the <ZH>Multiple objs allowed</>
indicator, so you cannot enter object tables for the class type under
<ZH>Objects</>.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

If you want to enter multiple objects for the class type, set the
indicator for the class type first.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CL668 - Class type &1 does not allow additional objects ?

  The SAP error message CL668 indicates that you are trying to add additional objects to a class type that does not permit it. This typically occurs when you are working with class types in the ABAP Object-Oriented programming environment, and it can happen in various scenarios, such as when trying to add attributes, methods, or other components to a class that is defined in a way that restricts such modifications.
  Cause:
  
  Class Type Restrictions: The class type you are working with may be defined as a final class or an interface that does not allow additional objects to be added.
  Inheritance Issues: If you are trying to extend a class that is not designed to be extended, you may encounter this error.
  System Configuration: Certain system settings or configurations may restrict modifications to specific class types.
  
  Solution:
  
  Check Class Definition: Review the class definition to ensure that it is not marked as final or an interface that restricts additional objects.
  Use Correct Class Type: If you need to add additional objects, consider using a different class type that allows for such modifications.
  Modify Inheritance: If you are trying to extend a class, ensure that the parent class is designed to be extended (i.e., it should not be declared as final).
  Consult Documentation: Refer to SAP documentation or the ABAP programming guidelines to understand the limitations of the class type you are working with.
  Seek Help from SAP Support: If you are unable to resolve the issue, consider reaching out to SAP support or consulting with a colleague who has experience with ABAP class design.
  
  Related Information:
  
  Class Types in ABAP: Familiarize yourself with the different class types in ABAP, such as abstract classes, interfaces, and final classes, to understand their limitations and capabilities.
  ABAP Object-Oriented Programming: Review the principles of object-oriented programming in ABAP, including inheritance, encapsulation, and polymorphism, to better understand how class types interact.
  SAP Notes and Community: Check SAP Notes for any known issues or updates related to class types and error CL668. Additionally, consider visiting SAP Community forums for discussions and solutions shared by other developers.
  
  By following these steps, you should be able to identify the cause of the error and implement a suitable solution.