public static void main(String[] args) { StringBuilder text = new StringBuilder("It's SO very RUDE to shout !"); Matcher m = Pattern.compile("\\b[\\p{Lu}\\p{Lt}]+\\b").matcher(text); while (m.find()) { text.replace(m.start(), m.end(), m.group().toLowerCase()); System.out.println(">>>>>> "+m.group(0)); }