You must note the following points when using the methods of the HttpHeaders interface:

• A return value of the getCookies() method includes the version information of Cookie (Example: "cookieName=$Version=0;cookieName=cookieValue").
• If you specify a language code other than those laid down in the ISO 639 standards, in the Content-Language header of a received HTTP message, the operation of the getLanguages() method is not guaranteed.
• When using the getRequestHeader(String name) method, null is returned when you try to acquire a value of a header that does not exist in the Http request.