web/src/main/java/org/springframework/security/web/authentication/rememberme/AbstractRememberMeServices.java
protected String extractRememberMeCookie(HttpServletRequest request) {
		Cookie[] cookies = request.getCookies();

		if ((cookies == null) || (cookies.length == 0)) {
			return null;
		}

		for (Cookie cookie : cookies) {
			if (cookieName.equals(cookie.getName())) {
				return cookie.getValue();
			}
		}

		return null;
	}
protected String extractRememberMeCookie(HttpServletRequest request) {
		Cookie[] cookies = request.getCookies();

		if ((cookies == null) || (cookies.length == 0)) {
			return null;
		}

		for (Cookie cookie : cookies) {
			if (cookieName.equals(cookie.getName())) {
				return cookie.getValue();
			}
		}

		return null;
	}
Locates the Spring Security remember me cookie in the request and returns its
value. The cookie is searched for by name and also by matching the context path to
the cookie path.

@param request the submitted request which is to be authenticated
@return the cookie value (if present), null otherwise.