@Override
public void onCreate() {
    super.onCreate();
    if (Build.VERSION.SDK_INT >= 26) {
        String CHANNEL_ID = "my_channel_01";
        NotificationChannel channel = new NotificationChannel(CHANNEL_ID,
                "My Channel",
                NotificationManager.IMPORTANCE_DEFAULT);

        ((NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE)).createNotificationChannel(channel);

        Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
                .setContentTitle("A service is running in the background")
                .setContentText("").build();

        startForeground(1, notification);
    }
}