To send and retrieve cookies, use the WebResponse and WebRequest objects, respectively. These in turn can be obtained from the RequestCycle, which can be retrieved by calling the getRequestCycle method on a Component. Thus to create a cookie:

        ((WebResponse)getRequestCycle().getResponse()).addCookie(new Cookie("cookieName", "cookieValue"));

and to retrieve all cookies:

        Cookie[] cookies = ((WebRequest)getRequestCycle().getRequest()).getCookies();

Alternatively, anywhere on the thread that is responding to a web request:

        ((WebResponse)RequestCycle.get().getResponse()).addCookie(new Cookie("cookieName", "cookieValue"));

and similarly for retrieving cookies.

Finally, the casts can be avoided if you are within a subclass of WebPage:

        getWebRequestCycle().getWebResponse().addCookie(new Cookie("cookieName", "cookieValue"));

and similarly for retrieving cookies.