I'm studying Android service and I have a question.

public class MainActivity extends AppCompatActivity {

    Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void onButton1Clicked(View v) {
        intent = new Intent(this, BaseService.class);
        startService(intent);
    }
    public void onButton2Clicked(View v) {
        intent = new Intent(this, BaseService.class);
        stopService(intent);
    }
}


///////////////////////////////////////////////////////////////////////////////////////


public class BaseService extends Service {

    Boolean running = true;
    int count = 1;
    public BaseService() {
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                while (running) {
                    try {
                        Log.d ("BaseService", count + "Burn service works");
                        count++;
                        Thread.sleep(1000);
                    } } catch (Exception e) {
                        Log.e("BaseService", e.toString());
                    }
                }
            }
        });
        thread.start();
        return super.onStartCommand(intent, flags, startId);
    }
    @Override
    public void onDestroy() {
        running = false;
        super.onDestroy();
    }
    @Override
    public IBinder onBind(Intent intent) {
        // // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }
}