private static void appendUnicode(@NlsSafe StringBuilder buffer, char ch) {
    String hexCode = StringUtil.toUpperCase(Integer.toHexString(ch));
    buffer.append("\\u");
    int paddingCount = 4 - hexCode.length();
    while (paddingCount-- > 0) {
      buffer.append(0);
    }
    buffer.append(hexCode);
  }
private static void appendUnicode(@NlsSafe StringBuilder buffer, char ch)