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WhizLab question

 
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Hi,


The _____ interface allows the class to have complete
control over its serialization



Fill in the blanks...


Thanks,
cmbhatt


(look no bang !)
[ April 26, 2007: Message edited by: Barry Gaunt ]
 
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From the Java API...


public interface Externalizable
extends Serializable
Only the identity of the class of an Externalizable instance is written in the serialization stream and it is the responsibility of the class to save and restore the contents of its instances. The writeExternal and readExternal methods of the Externalizable interface are implemented by a class to give the class complete control over the format and contents of the stream for an object and its supertypes. These methods must explicitly coordinate with the supertype to save its state. These methods supercede customized implementations of writeObject and readObject methods.
Object Serialization uses the Serializable and Externalizable interfaces. Object persistence mechanisms can use them as well. Each object to be stored is tested for the Externalizable interface. If the object supports Externalizable, the writeExternal method is called. If the object does not support Externalizable and does implement Serializable, the object is saved using ObjectOutputStream.
When an Externalizable object is reconstructed, an instance is created using the public no-arg constructor, then the readExternal method called. Serializable objects are restored by reading them from an ObjectInputStream.
An Externalizable instance can designate a substitution object via the writeReplace and readResolve methods documented in the Serializable interface.




 
Chandra Bhatt
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Thanks for posting API note for Externalizable!

Externalizable is quite strong than the Serializable interface. However I have not used it yet!



Thanks,
cmbhatt
 
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You know, whizlabs just got me on an Externalization question too. I didnt see anything in the K&B Book on it. (checked index and section in book)

Is this in fact on the test?

If so, I wonder what else is missing from the K&B Book.
 
Chandra Bhatt
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No Rob,

I should have not posted this question on this forum, because sometimes it causes confusion. Like you some others might have gone through index and contents of the book as well exam objective list. Actually Externalization is not on the Exam. But what to say of simulators. It is hard to be 100% specific.

Anyways Serialization is on the exam list; Externalization is subclass of Serialization.


cmbhatt
 
Rob Mech
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I was ok with the post I was just curious. According to whizlabs support they say that Serialization is on there and that Externalizable is part of it but frankly I dont believe it.

Hey, doesnt hurt to learn it.
 
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