Can you help me to tell the output of this program and how we are getting this....

[Bijendra S. Rajput]

Hi all,

any body can tell me what is the output of this program......

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 ) { }
}
}

What is the result?

A). pc
B). pcc
C). pcp
D). pcpc
E). Compilation fails
F). An exception is thrown at runtime

[Barry Gaunt]

Please tell us from which mock exam this question comes.
Thanks.

[Jesse Custer]

The answer should be C.

When you create the new instance of Cardplayer, first the super constructor is called wich prints 'p'. Then then constructor itself will print 'c'.

Now the object gets serialized and deserialized. Because Cardplayer is a subclass of Player wich is not serializable, all the parts of Cardplayer wich are inherited from Player will initialize in a normal way, wich means the constructor of Player will run. So again 'p' is printed.
The constructor of Cardplayer itself will not run because the state off all (non-transient) instance variables will be reconstructed on deserialization.

Greetings

Remark: this question comes from K&B book Chapter 6
[ February 14, 2007: Message edited by: Jesse Custer ]

[Bijendra S. Rajput]

Hi

I got this question from web page
by selecting this option.

Java 5 (310-055) SCJP questions by Kathy Sierra and Bert Bates (11 Qustions)

[Bijendra S. Rajput]

Hi Jesse,


Now I got.
Thanks a lot for telling so clear.