code: public void warn(String msg, Object[] args) throws TransformerException
    {
  
      java.lang.String fmsg = XSLMessages.createXPATHWarning(msg, args);
  
      if (null != m_errorHandler)
      {
        m_errorHandler.warning(new TransformerException(fmsg, m_locator));
      }
      else
      {
        System.out.println(fmsg
                            +"; file "+m_locator.getSystemId()
                            +"; line "+m_locator.getLineNumber()
                            +"; column "+m_locator.getColumnNumber());
      }
    }
docs: Warn the user of an problem.
  
  @param msg An error msgkey that corresponds to one of the constants found
  in {@link org.apache.xpath.res.XPATHErrorResources}, which is
  a key for a format string.
  @param args An array of arguments represented in the format string, which
  may be null.
  
  @throws TransformerException if the current ErrorListoner determines to
  throw an exception.