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Singleton two or more instances

Harikrishna Gorrepati
Ranch Hand

Joined: Sep 23, 2010
Posts: 423
Hi, The following is asked me several times during the interview
Question : Can we have singleton with 2 instances or 3 instances or more ? How to achieve that ?
My Answer : It cannot be more than 1 instance.
But interviewers are never happy with my answer even though I gave them the Singleton code. Please let me know how to get it. Please post code which helps me a alot.

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Rob Spoor

Joined: Oct 27, 2005
Posts: 19990

How does singleton allows the flexibility to create more objects if the situation changes.

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fred rosenberger
lowercase baba

Joined: Oct 02, 2003
Posts: 11739

Start a second JVM...

There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Stephan van Hulst

Joined: Sep 20, 2010
Posts: 3780

Personally I've always thought of the Singleton pattern as one that generally limits the amount of instances created, but not necessarily to a single instance. The name is misleading, but the general case makes more sense for a pattern.
Matthew Brown

Joined: Apr 06, 2010
Posts: 4530

fred rosenberger wrote:Start a second JVM...

Or just use a second class loader?

It could be that they're thinking about distributed which case unless you're doing something clever there's nothing to stop the separate components each creating an instance.
I agree. Here's the link:
subject: Singleton two or more instances