why restart the service

Question

i have a problem in my service, the service is runnig from MainActivity (i am doing test) and extends of service.

i want to use the service from foreground and background (when the app is closed) and i already have my first problem:

my service(have a counter that is displayed by LOG) is restarting when i close the app.

also i want to be able to use the service with the open app and close app, in other words to use both the Service Started and Link Service

public class MyService extends Service {

private Thread backgroundThread;
private boolean isRunning;

public MyService() {
    Log.e("MyService","constructor");
}

@Override
public void onCreate() {
    super.onCreate();
    isRunning = false;
}

@Override
public IBinder onBind(Intent intent) {
    // TODO: Return the communication channel to the service.
    throw new UnsupportedOperationException("Not yet implemented");
}

@Override
public int onStartCommand(final Intent intent, int flags, int startId) {
    Log.e("onStartCommand","Servicio Llamado");

    if (!this.isRunning) {
        Log.e("onStartCommand","hilo iniciandose");
        this.backgroundThread = new Thread(myTask);
        runTask();
    }

    return super.onStartCommand(intent, flags, startId);
}

@Override
public void onDestroy() {
    super.onDestroy();
    Log.e("onDestroy","servicio destuido");
}

private void runTask(){
    this.isRunning = true;
    this.backgroundThread.start();
}
private Runnable myTask = new Runnable() {
    public void run() {
        Log.e("myTask","hilo iniciado");
        int i = 0;
        do{
            pauseService();

            Log.e("myTask","hilo contador: "+i);
            //Toast.makeText(getApplicationContext(),"CONTADOR = "+j, Toast.LENGTH_SHORT).show(); //no working :(
            i++;
        }while (i<10);

        /*
        //linea de detencion del servicio
        //stopSelf();

        isRunning=false;

        backgroundThread.interrupt();

        //backgroundThread = new Thread(myTask);
        */
        Log.e("myTask","hilo cerrado");
    }
};
private void pauseService(){
    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}
}

In main Activity

 Intent intent = new Intent(MainActivity.this,MyService.class);
 intent.putExtra("iteraciones",10);
 startService(intent);

why because the service restarts when I close the application and how can I avoid it?