public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        MainService.get(this);
    }

}

public class MainService extends Service {
    public static Object sWait = new Object();
    public static MainService instance;

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

    public static MainService get(Context mContext) {
        if (instance == null) {
            Intent intent = new Intent(mContext, MainService.class);
            mContext.startService(intent);
        }
        while (true) {
            if (instance != null) {
                Log.v("myLogs", "all is good!");
                break;
            }
            synchronized (sWait) {
                try {
                    sWait.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
        return instance;
    }

    @Override
    public void onCreate() {
        Log.v("myLogs", "created!");
        instance = this;
        synchronized (sWait) {
            sWait.notify();
        }
    }

}