java.lang.IllegalArgumentException: Control character in cookie value or attribute

Version 0 cookie values are restrictive in allowed characters. It only allows URL-safe characters. This covers among others the alphanumeric characters (a-z, A-Z and 0-9) and only a few lexical characters, including -, _, ., ~ and %. All other characters are invalid in version 0 cookies.

Your best bet is to URL-encode those characters. This way every character which is not allowed in URLs will be percent-encoded in this form %xx which is valid as cookie value.

So, when creating the cookie do:

Cookie cookie = new Cookie(name, URLEncoder.encode(value, "UTF-8"));
// ...

And when reading the cookie, do:

String value = URLDecoder.decode(cookie.getValue(), "UTF-8");
// ...