code: protected void fail(RequestDetails theRequestDetails, ValidationResult theValidationResult) {
  		throw new UnprocessableEntityException(theRequestDetails.getServer().getFhirContext(), theValidationResult.toOperationOutcome());
  	}
docs: Fail the request by throwing an {@link UnprocessableEntityException} as a result of a validation failure.
  Subclasses may change this behaviour by providing alternate behaviour.