How To Fix CX704 - Internal error - change to class type in instance & not allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: CX - Nachrichten für Konfigurationsprozess

• Message number: 704

• Message text: Internal error - change to class type in instance & not allowed

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message CX704 - Internal error - change to class type in instance & not allowed ?

  The SAP error message CX704 indicates an internal error related to a change in class type for an instance that is not allowed. This typically occurs in the context of object-oriented programming within ABAP (Advanced Business Application Programming) when there is an attempt to change the type of an object instance that has already been created.
  Cause:
  
  Type Mismatch: The error often arises when there is an attempt to assign an object of one class type to a variable of another class type, especially if the variable has already been instantiated.
  Inheritance Issues: If you are working with class hierarchies, trying to assign a subclass object to a superclass reference incorrectly can lead to this error.
  Dynamic Type Changes: The error can occur if there is an attempt to change the type of an object dynamically at runtime, which is not permitted in ABAP.
  
  Solution:
  
  Check Object Instantiation: Ensure that the object is instantiated correctly and that you are not trying to change its type after it has been created.
  Use Proper Casting: If you need to work with different class types, ensure that you are using proper casting techniques. Use CAST or CASTING to safely convert between types when necessary.
  Review Class Definitions: Check the class definitions and ensure that the inheritance structure is correctly set up. Make sure that you are not trying to assign incompatible types.
  Debugging: Use the ABAP debugger to trace the execution flow and identify where the type change is attempted. This can help pinpoint the exact line of code causing the issue.
  Code Review: Review the code for any logic that might inadvertently lead to type changes. Look for any dynamic type assignments or incorrect use of polymorphism.
  
  Related Information:
  
  ABAP Object-Oriented Programming: Understanding the principles of object-oriented programming in ABAP can help prevent such errors. Familiarize yourself with concepts like inheritance, polymorphism, and encapsulation.
  SAP Notes and Documentation: Check SAP Notes for any known issues or patches related to this error. SAP's official documentation can also provide insights into best practices for object handling.
  Community Forums: Engaging with the SAP community through forums like SAP Community or Stack Overflow can provide additional insights and solutions from other developers who may have encountered similar issues.
  
  If the problem persists after trying the above solutions, consider reaching out to SAP support for further assistance, providing them with detailed information about the context in which the error occurs.