How to Exception Handler

Question

Hi Experts,
How to handle exception in WebDynpro  GP callable objects.
I created exception parameter in getdescription() method like
IGPExceptionInfo processExc1 = technicalDescription.addProcessException("USER_NOT_FOUND");
  processExc1.setNameKey("USER_KEY");
  processExc1.setDescriptionKey("USER_DESCRIPTION_KEY");
  processExc1.setFatal(true);
In my Process 2 levels, in block level i am able to see above created exception in exception tab. I create one extra action with same callable object mapped, this action is mapped to exception handler & selected repeat from dropdown.
If any exception occurs execute method(like UMException) how to call handler from coding. I tryed this code to call handler
String localizedMessage =textAccessor.getText("USER_NOT_FOUND");
  wdThis.wdFireEventTechnicalException(new GPTechnicalCallableObjectException(logger,localizedMessage,e));
this is not working...   
Please any one tell how to call handler from WebDynpro  callable object
Regards
Satya

Answer 1

Inside a UI side Exception handling task-flow How can I distinguish validation exception and other exceptions..?
Note: Validate entity method in EOImpl might be throwing validation exceptions. But it is not aware of any UI side exception handling.