I saw http response that contains this header:

Set-Cookie: JSESSIONIDSSO=null; path=/; Max-Age=0; Expires=Thu, 01-Jan-1970 00:00:00 GMT

I guess it is perfectly valid but this 'null' value is too much dev oriented to my taste.
This is coming (I guess) from:

private static String addRfc6265ResponseCookieToExchange(final Cookie cookie) {
final StringBuilder header = new StringBuilder(cookie.getName());
header.append("=");
header.append(cookie.getValue());