code: public static boolean isPunycode(String str) {
  		if (str == null) {
  			return false;
  		}
  		return (!IDN.toUnicode(str).equals(str));
  	}
docs: Determinates if a given string is in Punycode format.
  
  @param str
  The string which should be checked
  @return Boolean which shows if the string is punycoded or not.