code: private void _reportWarning(XMLReporter rep, String probType, String msg,
                                 Location loc)
          throws XMLStreamException
      {
          if (rep != null) {
              /* Note: since the problem occurs at DTD (schema) parsing,
               * not during validation, can not set reporter.
               */
              XMLValidationProblem prob = new XMLValidationProblem
                  (loc, msg, XMLValidationProblem.SEVERITY_WARNING, probType);
              rep.report(msg, probType, prob, loc);
          }
      }
docs: /*
  /////////////////////////////////////////////////////////
  Error handling
  /////////////////////////////////////////////////////////