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Singleton two or more instances

Harikrishna Gorrepati
Ranch Hand

Joined: Sep 23, 2010
Posts: 422
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
Sheriff

Joined: Oct 27, 2005
Posts: 19794
    
  20

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


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fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11499
    
  16

Start a second JVM...


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Stephan van Hulst
Bartender

Joined: Sep 20, 2010
Posts: 3649
    
  17

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
Bartender

Joined: Apr 06, 2010
Posts: 4492
    
    8

fred rosenberger wrote:Start a second JVM...

Or just use a second class loader?

It could be that they're thinking about distributed applications...in which case unless you're doing something clever there's nothing to stop the separate components each creating an instance.
 
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