dúvida em serializacao - kathy

import java.io.*;
 public class SerializaDog {
 
 	public static void main(String[] args) {
 		Collar c = new Collar(3);
 		Dog d = new Dog(c,7);
 		System.out.println("before: collar " + d.getCollar().getCollarSize());
 		try{
 			FileOutputStream fp = new FileOutputStream("dog.ser");
 			ObjectOutputStream oo = new ObjectOutputStream(fp);
 			oo.writeObject(d);
 			oo.close();
 		}catch(Exception e){
 			e.printStackTrace();
 		}
 		/*try{
 			FileInputStream a = new FileInputStream("dog.ser");
 			ObjectInputStream oi = new ObjectInputStream(a);
 			d=(Dog)oi.readObject();
 			oi.close();
 		}catch(Exception e){}
 		System.out.println("after : collar is " + d.getCollar().getCollarSize());*/
 	}
 }
 
 class Dog implements Serializable{
 	private Collar collar;
 	private int dogSize;
 	public Dog(Collar collar,int size){
 		this.collar=collar;
 		dogSize=size;
 	}
 	public Collar getCollar(){return collar;}
 }
 class Collar {
 	private int collarSize;
 	public Collar(int s){collarSize=s;}
 	
 	public int getCollarSize(){return collarSize;}
 	
 }