Difficulty with Android Push Notifications Guide

I am having difficulty following the Android Push Notifications Guide. (Android Push Tutorial | Parse)

Specifically, when I try to use the following two code snippets in my manifest file, Android Studio tells me the two classes can’t be resolved.

Further, when I search around for ParseFirebaseInstanceIdService, I see they are no longer useable and that I should use FirebaseMessagingService instead. See: android - Unresolved Class ParseFirebaseInstanceIdService in AndroidManifest - Stack Overflow

However, even with that change and creating a class that extends FirebaseMessagingService that overrides onNewToken() and onMessageReceived() my app does does receive the push notification.

What am I supposed to do instead to get parse working with Android through FCM?

I’ve continued to work on this without any success.

Here are some questions that may help me narrow down what is wrong with my notification chain. Hopefully someone here can help me understand these things so that I can effectively troubleshoot what is wrong.

How can I know if a Push Notification has made it from Parse on AWS to Google fcm? I see in Past Pushes there is a status column that states if the message is being “SENT” or is “SENDING”. What exactly do these each mean? Does sent mean that Google fcm confirmed receipt of the Push Notification back to Pase Server?

How can I know if Google fcm pushed that notification down to my devices?

I think this is an issue with Google fcm configuration because I turned on my old server and old app and tried notifications with the old code set. Notification did not work. This tells me that there may not be anything wrong with my new code set since I am facing the same issue in my old code set. The old code set was last used about a year ago.

This is where you’ll handle token refresh and incoming messages respectively. Here’s a basic example:
import com.parse.ParseInstallation;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class MyFirebaseMessagingService extends FirebaseMessagingService {

@Override
public void onNewToken(String token) {
    super.onNewToken(token);
    // Update Parse Installation with new FCM token
    ParseInstallation.getCurrentInstallation().setString("deviceToken", token);
    ParseInstallation.getCurrentInstallation().saveInBackground();
}

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    // Handle incoming messages here
}

}