some doubts in core java

hi,
i have some doubts in some core java topics. i am writing list of the questions. thanks a lot in advance.

1) can we clone a singleton instance? do we need to implement clonable interface for this? if so then why because clone method is available in Object class.
2) If we clone the object it will loose its singleton property. so to stop cloning what we can do?
3) if we serialize an object and De serialize it twice how many objects we will get?

If an object is meant to be a singleton, then you probably don't want to let it be cloned. Therefore, you should not implement the cloneable interface. And if you don't, calling the clone() method inherited from the Object class throws an exception, if i recall correctly.

So the answer to #2 is to not implement the cloneable interface.

Kaushik Baral wrote:
3) if we serialize an object and De serialize it twice how many objects we will get?

Why don't you write some code to find the answer?

Good article on clone in Java.

http://en.wikipedia.org/wiki/Clone_%28Java_method%29

Or you might find the 3rd chapter of the old edition of Bloch's Effective Java™ here. That tells you about clone(). Remember it is the old edition.