Background location updates stopped when app is killed mode

Question

My problem is i can get the location in background but once app is killed it stopped updating. i am storing the latitude and longitude into firebase once it's fetching from getlastlocation method. and foreground and background mode it's updating fine. but when i close like clearing all the background apps then it is stop updating.

public class MyBackgroundLocationService extends Service {
    private static final String TAG = MyBackgroundLocationService.class.getSimpleName();
    private FusedLocationProviderClient mLocationClient;
    private LocationCallback mLocationCallback;

    public MyBackgroundLocationService() {
    }

    @Override
    public void onCreate() {
        super.onCreate();
        mLocationClient = LocationServices.getFusedLocationProviderClient(getApplicationContext());
        mLocationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                if (locationResult == null) {
                    Log.d(TAG, "onLocationResult: location error");
                    return;
                }

                List<Location> locations = locationResult.getLocations();

                LocationResultHelper helper = new LocationResultHelper(getApplicationContext(), locations);

                helper.showNotification();

                helper.saveLocationResults();

                Toast.makeText(getApplicationContext(), "Location received: " + locations.size(), Toast.LENGTH_SHORT).show();

            }
        };
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        Log.d(TAG, "onStartCommand: called");

        startForeground(1001, getNotification());

        getLocationUpdates();

        return START_STICKY;
    }

    private Notification getNotification() {

        NotificationCompat.Builder notificationBuilder = null;
        notificationBuilder = new NotificationCompat.Builder(getApplicationContext(),
                App.CHANNEL_ID)
                .setContentTitle("Location Notification")
                .setContentText("Location service is running in the background.")
                .setSmallIcon(R.mipmap.ic_launcher)
                .setAutoCancel(true);

        return notificationBuilder.build();
    }

    private void getLocationUpdates() {

        LocationRequest locationRequest = LocationRequest.create();
        locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        locationRequest.setInterval(5000);
        locationRequest.setFastestInterval(4000);

        locationRequest.setMaxWaitTime(15 * 1000);

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            stopSelf();
            return;
        }

        mLocationClient.requestLocationUpdates(locationRequest, mLocationCallback, Looper.myLooper());

    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(TAG, "onDestroy: called");
        stopForeground(true);
        mLocationClient.removeLocationUpdates(mLocationCallback);
    }
}

so i am using foreground service to update location in background and it will show in notification those updates. once app is killed notification also disappeared. please please please anyone help me.

if you need more clear about question i will explain. please someone understand my pain