@ExceptionHandler({RegionNotFoundException.class, ResourceNotFoundException.class})
  @ResponseBody
  @ResponseStatus(HttpStatus.NOT_FOUND)
  public String handle(final RuntimeException e) {
    return convertErrorAsJson(e.getMessage());
  }
Handles both ResourceNotFoundExceptions and specifically, RegionNotFoundExceptions, occurring
when a resource or a Region (a.k.a. resource) does not exist in GemFire.
<p>

@param e the RuntimeException thrown when the accessed/requested resource does not exist in
       GemFire.
@return the String message from the RuntimeException.
geode-web-api/src/main/java/org/apache/geode/rest/internal/web/controllers/BaseControllerAdvice.java