I would like to few advtanages about the Sigleton Object.

I know the following things, plz correct me if i am wrong..

1. Singleton object can't have more than one copy bcz it is static.

2. We are not able create instance for singleton object bcz there is only one
constructor that too private.

3. But still we can clone this object using clone() method.

I would like to know following things:

1. Where it can be used.
2. What are the advantages of creating object as singleton.
3. Is there any dis advantage(s).
4. What are the precautions to be taken while writing Singleton class and
acessing singleton class.
5. Any useful links and discuion on this issue is appriciated...