AuthorizationCodeInstalledApp, unexpected behaviour

I'm writing a JavaFX application and I have a login button to get the credentials.
When the button is pressed the controller starts the google authentication, this piece of code opens the browser if StoredCredential is not present:

GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
                httpTransport
                , JSON_FACTORY
                ,clientSecrets
                , scope)
                .setAccessType("offline")
                .setDataStoreFactory(dataStoreFactory)
                .setApprovalPrompt("auto")
                .build();

LocalServerReceiver serverReceiver = new LocalServerReceiver.Builder().setPort(8888).build();
credentials = new AuthorizationCodeInstalledApp(flow, serverReceiver).authorize("user");

While this code is executed the app thread is waiting so the app is irresponsive. I tried to close the browser to see what would happen in this case, the app is still irresponsive.

How could I solve it? Should I run the authorization code in a separate thread and proceed only if credentials are valid?

So, after doing some research I found that this issue has been reported two years ago on the "Google OAuth Client Library for Java" repository on GitHub, here #175 and here #182.
As suggested I tried to use JavaFX WebView but it has some issues as well, probably because it's a bit obsolete. I could get the credentials but I could not reach the "Received verification code. You may now close this window" page.

There are some alternatives to WebView like JxBrowser or JCEF however the first one is crazy expensive and the latter is not easy to implement in JavaFX.

I ended up using the installed browser and running the authentication flow in a separate thread. The login button is disabled for 90sec and a countdown animation starts using JavaFX Timeline. Every second it checks if credentials are valid. After 90sec the timeline stops and if credentials are still not valid it checks if the Thread is still running and stops it.

Here is the code:

GoogleAuthentication authentication = new GoogleAuthentication();
Task<Void> oauthTask = new Task<>() {
    @Override
    protected Void call() throws Exception {
        authentication.init();
        return null;
    }
};
Thread oauthThread = new Thread(oauthTask);
oauthThread.setDaemon(true);
AtomicInteger waitTime = new AtomicInteger(90);
loginButton.setDisable(true);
loginButton.setText(waitTime + "s");
Timeline timeline = new Timeline();
timeline.setCycleCount(Animation.INDEFINITE);
timeline.getKeyFrames().add(
        new KeyFrame(Duration.seconds(1), event -> {
            if (isValidCredentials(authentication.getCredentials())) {
                resetButton(timeline);
                System.out.println(authentication.getCredentialsExpiration());
                return;
            }
            waitTime.getAndDecrement();
            loginButton.setText(waitTime + "s");
            if (waitTime.intValue() <= 0) {
                oauthThread.stop();
                resetButton(timeline);
            }
        })
);
timeline.play();
oauthThread.start();

<s>Yes, I know I shouldn't use the Thread.stop() method, I know it's deprecated, but it's the only way to make it work otherwise the LocalServerReceiver used for the authentication throws this exception "java.net.BindException: Address already in use: bind".
I tried with interrupt() but the thread just keeps waiting, thanks Google for your... "not so good" implementation I guess.</s>
Better solution, keep the LocalServerReceiver as an instance variable, use a getter and use the stop() method.

So this oauthThread.stop(); becomes authentication.getServerReceiver().stop(); surrounded by try\catch IOException

This is my solution so far, I have to admit it's my first time working with threads and concurrency for real. If you have any other ideas or improvements please comment out.

Take a look here: https://docs.oracle.com/javafx/2/webview/jfxpub-webview.htm

Docs on using and interacting with pop-up windows