Related to Object Serialization

[Ali Gohar]

Hi,

The following code prints "pcp" whereas i think it should print "pcpc". Can anybody explains why it prints "pcp"?

    
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 ) { }
  }
}

[Barry Gaunt]

How about you explaining why you think it prints that final "c"?

[Burkhard Hassel]

Hi Ali,

i think it should print "pcpc"

First think about, what Barry said, but if you don't get it, see below the "spoiler".













spoiler

The last c will not print, because in deserialization, the constructors of classes implementing Serializable will not run.
Only constructors of superclasses not implementing Serializable will run.

If you have the K&B book, you can look it up on pages 453 and the following.



Yours,
Bu.
[ October 06, 2006: Message edited by: Burkhard Hassel ]

[Ali Gohar]

I think that when it will read the object from serialized file, it will create new CardPlayer() and will then set the values, so if its true then again "pc" should be printed making "pcpc", but i know i am wrong

Can you explain why?

[Ali Gohar]

Thanks BH, i got that