How To Fix CL537 - Class type "&" is different to valid class type "&"

SAP Error Message - Details

• Message type: E = Error

• Message class: CL - Classification

• Message number: 537

• Message text: Class type "&" is different to valid class type "&"

What causes this issue?

The class type of the first allocation record is compared with the
others. If the class types are different, the record is ignored.

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?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CL537 - Class type "&" is different to valid class type "&" ?

  The SAP error message CL537 indicates that there is a mismatch between the class type of the object you are trying to work with and the expected class type in the system. This typically occurs in the context of object-oriented programming in ABAP, particularly when dealing with class definitions and instantiations.
  Cause:
  
  Class Type Mismatch: The error arises when you attempt to use a class or object of a certain type that does not match the expected class type. For example, if you are trying to instantiate a class of type "ZCL_MY_CLASS" but the system expects a class of type "CL_MY_EXPECTED_CLASS", this error will occur.
  Inheritance Issues: If the class you are trying to use is not a subclass of the expected class type, this can also lead to this error.
  Incorrect Type Declaration: The variable or parameter may have been declared with the wrong class type, leading to a mismatch when the code is executed.
  
  Solution:
  
  Check Class Definitions: Verify the class definitions and ensure that the class you are trying to use is indeed of the expected type. You can do this by checking the class type in the Class Builder (transaction SE24).
  Correct Type Declaration: Ensure that the variable or parameter is declared with the correct class type. If you are expecting a certain class type, make sure that the variable is declared accordingly.
  Review Inheritance: If you are working with inheritance, ensure that the class you are using is a subclass of the expected class type. If not, you may need to adjust your class hierarchy.
  Debugging: Use the debugger to trace the execution and see where the mismatch occurs. This can help you identify the exact point in the code where the error is triggered.
  
  Related Information:
  
  Class Types in SAP: In SAP, classes can be of different types, such as local classes, global classes, and interface classes. Understanding the differences and how they relate to each other is crucial.
  ABAP Object-Oriented Programming: Familiarize yourself with the principles of object-oriented programming in ABAP, including class definitions, inheritance, and polymorphism.
  SAP Documentation: Refer to the official SAP documentation for more detailed information on class types and error handling in ABAP.
  
  By following these steps, you should be able to resolve the CL537 error and ensure that your code is functioning as expected.