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Serializable question

Chandra Bhatt
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Joined: Feb 28, 2007
Posts: 1707

10. class Car implements Serializable {
11. Wheels w;
12. }
13.
14. class Wheels { }

If you attempt to serialize an instance of Car, what is the result?

A. Compilation fails.
B. One object is serialized.
C. Two objects are serialized.
D. An exception is thrown at runtime.


What will be the correct answer?


Source: Sun practice exam


[EDIT] YEAH Swarna, I say that too, but the source says 'B'.
Surprised!!!

Thanks,
cmbhatt
[ April 27, 2007: Message edited by: Chandra Bhatt ]

cmbhatt
swarna dasa
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Joined: Mar 15, 2007
Posts: 108
how abt D?
megha joshi
Ranch Hand

Joined: Feb 20, 2007
Posts: 206
Ya they say that
I understand it as follows:

Wheels is a object which cannot be serialized. Cars can be serialized. Wheels is not instantiated yet inside Cars so Cars object does not have Wheels object. Thus Cars object can be serialized and one object gets serialized. If Wheels object would have been instantiated then the Cars object would have a wheels object inside it and in that case that object cannot be serialized. It would throw NotSerializable exception then.

Its not easy to be a compiler
[ April 27, 2007: Message edited by: megha joshi ]
swarna dasa
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Joined: Mar 15, 2007
Posts: 108
should have guessed it, if it was as simple as D, you wouldn't have posted it in the first place
Chandra Bhatt
Ranch Hand

Joined: Feb 28, 2007
Posts: 1707
Yeah, You took the question in right way!

Until, Wheels is instantiated, no problem to serialize the Cars object,
which HAS-A Wheels.



Its not easy to be a compiler.


But I am sure It not easy to think like a programmer, for the compiler.



Thanks,
cmbhatt
Barry Gaunt
Ranch Hand

Joined: Aug 03, 2002
Posts: 7729
Just one small point. I take it that this question is not one of those from Sun's Practive Exam that you have agreed to not to disclose? That is, it is not from Sun's online US$ 75 test?
[ April 28, 2007: Message edited by: Barry Gaunt ]

Ask a Meaningful Question and HowToAskQuestionsOnJavaRanch
Getting someone to think and try something out is much more useful than just telling them the answer.
Abdul Mohsin
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Joined: Apr 26, 2007
Posts: 111

10. class Car implements Serializable {
11. Wheels w;
12. }
13.
14. class Wheels { }


just check the answer when we create new Wheels

Wheels w= new Wheels();


Thanks,

Abdul Mohsin


Regards, Abdul Mohsin
Rahul Bhattacharjee
Ranch Hand

Joined: Nov 29, 2005
Posts: 2308
Originally posted by swarna dasa:
how abt D?


I too go with D.


Rahul Bhattacharjee
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Chandra Bhatt
Ranch Hand

Joined: Feb 28, 2007
Posts: 1707
Hi all,


class Car implements Serializable {
Wheels w;
}

class Wheels { }



I do agree with you all, but only when a new instance of the Wheels is created. In this question option "B" is correct. Having only a reference of
the class that is not Serializable is no more sin that could hinder the proper Serialization of the containing class object.

Megha described the rest part very well.

Barry, the question I picked from says "Courtesy to sun practice exam"!
What to do, should I remove this question?
[ April 30, 2007: Message edited by: Chandra Bhatt ]
 
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subject: Serializable question