How To Fix FDT_EXPRESSIONS030 - No valid class, &1 does not exist or does not implement interface &2

SAP Error Message - Details

• Message type: E = Error

• Message class: FDT_EXPRESSIONS - Formula & Derivation Tool: Expressions

• Message number: 030

• Message text: No valid class, &1 does not exist or does not implement interface &2

What causes this issue?

You have tried to call a class method, but the system has determined a
problem. There are two possible causes for this message:
Class &v1& to which the method belongs does not exist.
You are using the old variant of the static method call and the chosen
class &v1& does not implement interface &v2&.

System Response

The system cannot process the method call.

How to fix this error?

Regardless of the error reasons mentioned above, you have to choose a
valid class.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FDT_EXPRESSIONS030 - No valid class, &1 does not exist or does not implement interface &2 ?

  The SAP error message FDT_EXPRESSIONS030 indicates that there is an issue with a class or interface in the context of the SAP Fiori Data Transformation (FDT) framework. Specifically, the error message states that a valid class does not exist or that the specified class does not implement the required interface.
  Cause:
  
  Missing Class: The class specified in the error message does not exist in the system. This could be due to a missing transport or an incorrect configuration.
  Incorrect Implementation: The class exists but does not implement the required interface. This could happen if the class was modified or if the wrong class was assigned to a particular task.
  Namespace Issues: The class might be in a different namespace that is not accessible or not properly defined in the system.
  Transport Issues: If the class was recently transported from another system, there may have been issues during the transport process.
  
  Solution:
  
  Check Class Existence: Verify that the class mentioned in the error message exists in the system. You can do this by using transaction SE24 (Class Builder) to search for the class.
  Check Interface Implementation: If the class exists, check whether it implements the required interface. You can do this by viewing the class definition in SE24 and checking the "Interfaces" tab.
  Correct Configuration: If the class is not implementing the required interface, you may need to modify the class to implement it correctly or replace it with a valid class that does.
  Namespace Verification: Ensure that the class is in the correct namespace and that there are no access issues.
  Transport Check: If the class was recently transported, check the transport logs for any errors and ensure that all necessary objects were included in the transport.
  Consult Documentation: Review any relevant documentation or notes related to the specific FDT implementation you are working with, as there may be specific requirements or known issues.
  
  Related Information:
  
  Transaction Codes: Use SE24 for class management, SE80 for object navigation, and SE37 for function module management if needed.
  SAP Notes: Check SAP Notes for any known issues related to the FDT framework or specific classes/interfaces you are working with.
  Debugging: If you have access to debugging tools, you can set breakpoints to trace where the error occurs in the code execution.
  Community Forums: Consider checking SAP Community or other forums for similar issues and solutions shared by other users.
  
  By following these steps, you should be able to identify the root cause of the error and implement a solution.