$.get({
            url: '/startChat',
            async: true,
            success: function (msgToAdd, textStatus, jqXHR) {
                alert(msgToAdd)
            },
            error: function (jqXHR, textStatus, errorThrown) {
                alert(errorThrown);
            }
        });

private HttpServletResponse firstResponse;
    @RequestMapping(value = "/startChat", method = RequestMethod.GET)
        public void startUserChat(HttpServletRequest request, HttpServletResponse response) {
    firstResponse = response;
    }