code: private static String msg(String errorMessage, String logMessage, int errorStart, int errorEnd) {
      if (errorEnd < 0) {
        errorEnd = logMessage.length();
      }
      StringBuilder out = new StringBuilder(errorMessage).append(": ");
      if (errorStart > SNIPPET_LENGTH + ELLIPSIS.length()) {
        out.append(ELLIPSIS).append(logMessage, errorStart - SNIPPET_LENGTH, errorStart);
      } else {
        out.append(logMessage, 0, errorStart);
      }
      out.append('[').append(logMessage.substring(errorStart, errorEnd)).append(']');
      if (logMessage.length() - errorEnd > SNIPPET_LENGTH + ELLIPSIS.length()) {
        out.append(logMessage, errorEnd, errorEnd + SNIPPET_LENGTH).append(ELLIPSIS);
      } else {
        out.append(logMessage, errorEnd, logMessage.length());
      }
      return out.toString();
    }
docs: Helper to format a human readable error message for this exception.