static class CookiesHandler implements HttpHandler {
        public void handle(HttpExchange exchange) throws IOException {
            String response = "Hello World!";

            exchange.getResponseHeaders().set("Set-cookie", "ciaseczko2=testoweCiasteczko3; domain=localhost; path=/echo/");

            exchange.getResponseHeaders().set("Content-Type", "text/plain; charset=UTF-8");

            String jsonString = JsonWriter.objectToJson(exchange.getResponseHeaders());
            response = JsonWriter.formatJson(jsonString);

            exchange.sendResponseHeaders(200, response.length());
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }

static class AuthHandler implements HttpHandler {
        public void handle(HttpExchange exchange) throws IOException {
            String response = "Hello World!";

            String user = "u";
            String pass = "p";
            String userAndPass = user + ":" + pass;

            String auth = exchange.getRequestHeaders().getFirst("Authorization");

            if(auth==null){
                notLogin(exchange,response);
            } else {
                if(auth.startsWith("Basic ")){
                    String creds = auth.substring(6);
                    byte[] decoded = javax.xml.bind.DatatypeConverter.parseBase64Binary(creds);
                    String responseUserAndPassword = new String(decoded, "UTF-8");
                    if(responseUserAndPassword.equals(userAndPass)){
                        response = "zalogowany";
                        exchange.getResponseHeaders().set("Content-Type", "text/plain; charset=utf-8");
                        exchange.sendResponseHeaders(200, response.length());
                        OutputStream os = exchange.getResponseBody();
                        os.write(response.getBytes());
                        os.close();
                    }else{
                        notLogin(exchange,response);
                    }
                }
            }
        }

        public void notLogin(HttpExchange exchange, String response) throws IOException{
            exchange.getResponseHeaders().set("WWW-Authenticate", "Basic");
            exchange.sendResponseHeaders(401, 0);
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }

static class Auth2Handler implements HttpHandler {
        public void handle(HttpExchange exchange) throws IOException {
            String response = "Hello World!";

            response = "Hello " + exchange.getPrincipal().getUsername();

            exchange.getResponseHeaders().set("Content-Type", "text/plain; charset=UTF-8");
            exchange.sendResponseHeaders(200, response.length());
            OutputStream os = exchange.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }

main(){
    ...
    HttpContext auth2 = server.createContext("/auth2/", new Auth2Handler());
        auth2.setAuthenticator(new BasicAuthenticator("user:a, password:p"){
            @Override
            public boolean checkCredentials(String user, String pwd) {
                return user.equals("a") && pwd.equals("p");
            }
        });
}