Whenever invalid xml character comes xml, it gives such error. When u open it in notepad++ it look like VT, SOH,FF like these are invalid xml chars. I m using xml version 1.0 and i validate text data before entering it in database by pattern
Pattern p = Pattern.compile("[^\u0009\u000A\u000D\u0020-\uD7FF\uE000-\uFFFD\u10000-\u10FFF]+");
retunContent = p.matcher(retunContent).replaceAll("");
It will ensure that no invalid special char will enter in xml