Otto issue

OttoIssue.java

package com.example.provaandroid;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

import com.squareup.otto.Bus;
import com.squareup.otto.Produce;
import com.squareup.otto.Subscribe;

public class MyActivity extends Activity {

	public static class Father {
		@Override
		public String toString() {
			return "I am father - " + super.toString();
		}
	}

	public static class Son extends Father {
		@Override
		public String toString() {
			return "I am son - " + super.toString();
		}
	}

	private Bus bus;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		bus = new Bus();
		bus.register(this);
		
		Log.e("MyActivity", "------------");
		
		bus.post(new Son());
		
//		actual output is:
//		04-30 09:14:06.676: E/getFather(1801): got father I am father - com.example.provaandroid.MyActivity$Father@b579d0d8
//		04-30 09:14:06.676: E/getSon(1801): got son I am son - I am father - com.example.provaandroid.MyActivity$Son@b579d740
//		04-30 09:14:06.676: E/MyActivity(1801): ------------
//		04-30 09:14:06.676: E/getFather(1801): got father I am son - I am father - com.example.provaandroid.MyActivity$Son@b579de40
//		04-30 09:14:06.676: E/getSon(1801): got son I am son - I am father - com.example.provaandroid.MyActivity$Son@b579de40
		
//		extected is:
//		04-30 09:14:06.676: E/getFather(1801): got father I am father - com.example.provaandroid.MyActivity$Father@b579d0d8
//		04-30 09:14:06.676: E/getSon(1801): got son I am son - I am father - com.example.provaandroid.MyActivity$Son@b579d740
//		04-30 09:14:06.676: E/MyActivity(1801): ------------
//		04-30 09:14:06.676: E/getSon(1801): got son I am son - I am father - com.example.provaandroid.MyActivity$Son@b579de40
	}

	@Subscribe
	public void getFather(Father father) {
		Log.e("getFather", "got father " + father);
	}

	@Subscribe
	public void getSon(Son son) {
		Log.e("getSon", "got son " + son);
	}
	
	@Override
	protected void onDestroy() {
		super.onDestroy();
		bus.unregister(this);
	}
	
	@Produce
	public Father produceFather() {
		return new Father();
	}
	
	@Produce
	public Son produceSon() {
		return new Son();
	}
}