Doubt in Serialization

[gobburi saikrishna]

Hello Ranchers
This is the question from SCJP(310-055) exam guide by kathy Siera and Bert Bates, page no:501 Question no:6

import java.io.*;
Class Keyboard
{
}
public class Computer implements Serializable
{
private Keyboard k=new Keyboard();
public static void main(String[]args)
{
Computer c=new Computer();
c.storeIt(c);
}
void storeIt(Computer c)
{
try{
ObjectOutputStream os=new ObjectOutputStream(new FileOutputStrea("myfile"));
os.writeObject(c);
os.close();
System.out.println("done");
}
catch(Exception e)
{
System.out.println("exe");
}
}
}
Answers(choose all the apply)
a)exe
b)done
c)Compilation fails
d)Exactly one object is serialized
e)exactly two objects are serialized

answer is given as A, my doubt why cant answer be A,B and D, because here only one object is Serialized that is c.
[ February 09, 2008: Message edited by: gobburi saikrishna ]

[Ulf Dittmer]

Please UseCodeTags and QuoteYourSources.

[Ian Edwards]

The reason the answer is A is that the Computer class has a private instance variable of type Keyboard.

When you attempt to serialize the Computer class it fails due to the Keyboard class not implementing Serializable. To overcome this problem either implement Serializable on the Keyboard class or add the transient modifier to the reference variable.

[Vishwanath Krishnamurthi]

Hi,

my doubt why cant answer be A,B and D, because here only one object is Serialized that is c.

Here, as an exception occurs at runtime while trying to serialize a Keyboard, the exception is being caught in catch block - so ya, A is fine.

But after the exception is caught the execution starts from the statement that follows the catch block

os.writeObject(c);
os.close(); //not here    

So b and d gotto be wrong..

Regards,
Vishwa

[Vikram Shinde]

as class Keyboard is not implementing Serializable or the object reference variable (instance of class Computer) is not transient
so while serialization it will throw Runtime Exception -
java.io.NotSerializableException: Keyboard
so in catch block it will print "exe" instead of "done" of try block
so A is right answer