How To Fix FDT_CORE147 - No valid class, &1 does not exist or does not implement interface &2

SAP Error Message - Details

• Message type: E = Error

• Message class: FDT_CORE - Formula & Derivation Tool: Core

• Message number: 147

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

What causes this issue?

The signature of an BRFplus expression type is defined by an ABAP-OO
interface. The functionality is defined in an ABAP-OO class implementing
that interface. This class also needs to implement the interface
IF_FDT_EXPRESSION.
Optionally there can be further classes defined for an expression type.
These are a query class, a UI class and a data exchange class. For a
detailed description of the functionality provided by these classes,
refer to the BRFplus documentation. If one of the classes is set it
needs to implement a corresponding interface.
These are the following:
The query class needs to implement IF_FDT_OBJECT_QUERY
The UI class needs to implement IF_FDT_UI_DEFINITION
The data exchange class needs to implement IF_FDT_DATA_EXCHANGE_EXTERNAL

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?

Specify a correct interface and correct classes for the expression type.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FDT_CORE147 - No valid class, &1 does not exist or does not implement interface &2 ?

  The SAP error message FDT_CORE147 indicates that there is an issue with a class not being valid or not implementing a required interface. This error typically arises in the context of SAP's Flexible Data Import (FDI) or Flexible Data Transfer (FDT) framework, which is used for data handling and processing.
  
  Cause:
  
  Class Not Found: The specified class (&1) does not exist in the system. This could be due to a typo in the class name or the class not being activated.
  Interface Not Implemented: The class exists but does not implement the required interface (&2). This means that the class is not fulfilling the contract defined by the interface, which is necessary for the operation to proceed.
  Transport Issues: If the class was recently transported from another system, it may not have been transported correctly, or dependencies may be missing.
  Authorization Issues: The user may not have the necessary authorizations to access the class or