Android - Parse JSON Array from FCM Notifications : https://stackoverflow.com/a/55428420/1318946

MyFirebaseMessagingService.java

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMessagingServ";
    private static int NOTIFICATION_ID = 1;

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);

        // Check if message contains a data payload.
        if (remoteMessage.getData().size() > 0) {
            Log.d(TAG, "remoteMessage.getData() : " + remoteMessage.getData());

            JSONObject object = new JSONObject(remoteMessage.getData());

            Log.d(TAG, "new JSONObject(remoteMessage.getData()) : " + object.toString());

            String finalJSON = object.toString().replaceAll("\\\\", "").replace("\"[", "[").replace("]\"", "]");

            Log.d(TAG, "Replace all back slash and invalid double quotes : " + finalJSON);

            CommonNotificationBean bean = new Gson().fromJson(finalJSON, CommonNotificationBean.class);

            sendNotification(bean);
        }
    }

    @Override
    public void onNewToken(String s) {
        super.onNewToken(s);
        Log.d("TAG", "TOKEN : " + s);
        Preference.setPushToken(this, s);
    }
  
  private void sendNotification(CommonNotificationBean notificationBean) {
        String textTitle = notificationBean.getTitle();

        String notificationType = notificationBean.getNotificationType();

        Intent intent = new Intent(this, DriverStatusActivity.class);

        switch (notificationType) {
            case NOTIFICATION_ACCEPT_REQUEST:
                intent.putExtra(NOTIFICATION_ACCEPT_REQUEST, new Gson().toJson(notificationBean));
                break;
            case Constants.NOTIFICATION_ARRIVE_REQUEST:
                break;
            case Constants.NOTIFICATION_START_REQUEST:
                break;
            case Constants.NOTIFICATION_END_REQUEST:
                break;
            case Constants.NOTIFICATION_ACCEPT_SCHEDULE_REQUEST:
                break;
            case Constants.NOTIFICATION_LATER_START_NOTIFICATION_USER:
                break;
        }

        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, NOTIFICATION_ID, intent, PendingIntent.FLAG_ONE_SHOT);

        String channelName = getString(R.string.app_name);

        NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, channelName)
                .setSmallIcon(R.drawable.ic_stat_name)
                .setContentTitle(textTitle)
                .setContentText(notificationBean.getAlert())
                .setAutoCancel(true)
                .setContentIntent(pendingIntent)
                .setPriority(NotificationCompat.PRIORITY_DEFAULT);

        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            CharSequence name = getString(R.string.app_name);
            String description = getString(R.string.app_name);
            int importance = NotificationManager.IMPORTANCE_DEFAULT;

            NotificationChannel channel = new NotificationChannel(channelName, name, importance);
            channel.setDescription(description);

            AudioAttributes attributes = new AudioAttributes.Builder()
                    .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                    .setUsage(AudioAttributes.USAGE_NOTIFICATION)
                    .build();
            Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

            channel.enableLights(true);
            channel.enableVibration(true);
            channel.setSound(soundUri, attributes);

            // Register the channel with the system; you can't change the importance
            // or other notification behaviors after this
            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }

        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);

        // notificationId is a unique int for each notification that you must define
        notificationManager.notify(NOTIFICATION_ID++, mBuilder.build());
    }
}