code: public boolean data_setCookie(Integer userId, CharSequence cookieName, CharSequence cookieValue)
      throws FacebookException, IOException {
      return data_setCookie(userId, cookieName, cookieValue, /*expiresTimestamp*/null, /*path*/ null);
    }
docs: Sets a cookie for a given user and application.
  @param userId The user for whom this cookie needs to be set
  @param cookieName Name of the cookie.
  @param cookieValue Value of the cookie.
  @return true if cookie was successfully set, false otherwise
  @see <a href="http://wiki.developers.facebook.com/index.php/Data.getCookies">
  Developers Wiki: Data.setCookie</a>
  @see <a href="http://wiki.developers.facebook.com/index.php/Cookies">
  Developers Wiki: Cookies</a>