class TestActionListener implements ActionListener{
    static volatile ArrayList<String> usernames = new ArrayList<String>();
    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("START");
        ArrayList<Integer> user_ids = new ArrayList<Integer>();

        for (int i = 100; i < 500; i++) {
            user_ids.add(i);
        }

        long time = System.currentTimeMillis();

        String url;
        ExecutorService exec = Executors.newFixedThreadPool(4);
        for (int i = 0; i < user_ids.size(); i++){
            url = Main.BASE_URL + "member/" + user_ids.get(i);
            try {
                usernames.add(exec.submit(new MyCallable(url)).get());
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            } catch (ExecutionException ex) {
                ex.printStackTrace();
            }
        }
        exec.shutdown();

        System.out.println(usernames.size());

        for (int i = 0; i < usernames.size(); i++) {
            System.out.println(usernames.get(i));
        }
        System.out.println(System.currentTimeMillis() - time);

        System.out.println("END");

    }

}


class MyCallable implements Callable<String> {

    private String url;

    public MyCallable(String url) {
        this.url = url;
    }

    @Override
    public String call() {
        try {
            return Tesla.session.get(url)
                    .execute()
                    .parse()
                    .getElementsByClass("username")
                    .first()
                    .text();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }
}