How To Fix CL655 - Multiple objects must have more than one class type

SAP Error Message - Details

• Message type: E = Error

• Message class: CL - Classification

• Message number: 655

• Message text: Multiple objects must have more than one class type

What causes this issue?

One of the two class types allows you to classify objects of more than
one object type (for example, materials and batches). However, in the
other class type, only objects of one object type (for example,
materials) can be classified.
In this case, you cannot split or merge classes of the two class types.
Example:
You cannot classify batches in a class type that is only defined for
materials.

System Response

The system compares the <LS>Several objs allowed</> field in the class
type table.

How to fix this error?

Please choose your class types such that either both allow you to
classify objects of different object types or both allow you to
classify only objects of one object type.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CL655 - Multiple objects must have more than one class type ?

  The SAP error message CL655, which states "Multiple objects must have more than one class type," typically occurs in the context of class or object management in ABAP programming or when working with class-based programming in SAP.
  Cause:
  This error usually arises when you are trying to perform an operation that involves multiple objects, but the system expects those objects to belong to different class types. The error indicates that the operation you are attempting is not valid because the objects do not meet the required criteria for class types.
  Common Scenarios:
  
  Inheritance Issues: You might be trying to instantiate or manipulate objects that are expected to be of different subclasses, but they are not.
  Method Calls: If you are calling a method that requires parameters of different class types, and you provide parameters of the same class type, this error can occur.
  Interface Implementation: If you are working with interfaces and trying to pass multiple objects that do not implement the required interfaces correctly.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Object Types: Ensure that the objects you are working with are of the correct class types. If you are passing multiple objects, verify that they are of different types as required by the operation.
  
  
  Review Class Definitions: Look at the class definitions and inheritance structure. Make sure that the classes are correctly defined and that the objects you are using are instantiated from the correct classes.
  
  
  Modify Method Signatures: If you are calling a method, check the method signature to ensure that it can accept the types of objects you are passing. You may need to overload the method or change the parameter types.
  
  
  Debugging: Use debugging tools in SAP to trace the execution and see where the error is being triggered. This can help you identify the specific objects and their types involved in the operation.
  
  
  Consult Documentation: Review SAP documentation or the ABAP programming guidelines for more information on class types and object-oriented programming in SAP.
  
  
  Related Information:
  
  ABAP Object-Oriented Programming: Familiarize yourself with the principles of object-oriented programming in ABAP, including class definitions, inheritance, and polymorphism.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message.
  Community Forums: Engage with SAP community forums or support channels for additional insights and solutions from other developers who may have encountered similar issues.
  
  By following these steps, you should be able to identify the root cause of the CL655 error and implement a suitable solution.