Serialization doubt

[ram shah]

source : http://www.javabeat.net/javabeat/scjp5/mocks/MockExam02.php

 
 
import java.io.*;
class Player {
  Player() { System.out.print("p"); }
}
class CardPlayer extends Player implements Serializable {
  CardPlayer() { System.out.print("c"); }
  public static void main(String[] args) {
    CardPlayer c1 = new CardPlayer();
    try {
      FileOutputStream fos = new FileOutputStream("play.txt");
      ObjectOutputStream os = new ObjectOutputStream(fos);
      os.writeObject(c1);
      os.close();
      FileInputStream fis = new FileInputStream("play.txt");
      ObjectInputStream is = new ObjectInputStream(fis);
      CardPlayer c2 = (CardPlayer) is.readObject();
      is.close();
    } catch (Exception x ) { }
  }
}
   

My doubt is howcome it prints "pcp"? I thought it will be "pc".

[dolly shah]

When you implement Serializable in a subclass whose superclass is not implementing Serializable, whenever you deserialized the subclass object only superclass constructor runs. So after line 1 you get "pc"(constructor runs) & after line 2 you get "p". So your output is "pcp". This example is from K & B book, chaper:6. They have given good description.

import java.io.*;
class Player {
  Player() { System.out.print("p"); }
}
class CardPlayer extends Player implements Serializable {
  CardPlayer() { System.out.print("c"); }
  public static void main(String[] args) {
    CardPlayer c1 = new CardPlayer();//line 1
    try {
      FileOutputStream fos = new FileOutputStream("play.txt");
      ObjectOutputStream os = new ObjectOutputStream(fos);
      os.writeObject(c1);
      os.close();
      FileInputStream fis = new FileInputStream("play.txt");
      ObjectInputStream is = new ObjectInputStream(fis);
      CardPlayer c2 = (CardPlayer) is.readObject();//line 2 
      is.close();
    } catch (Exception x ) { }
  }
}
   

[Lucky J Verma]

when deserializing,
The class's contructor doesnt run again but parent class's does(if parent class not implementing serializable)