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Wrapper classes are immutable

 
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Please explain the following:

"All wrapper classes are immutable, once created their values can't be changed".


Please give an example of the above.
 
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it means that when your code is like


internaly it goes like

The values that contained in the wrapper don't change, when some operations are made on them, it means new wrapper objects are created and assigned to you wrapper references.
 
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Some more information on what "immutable" means:

Mutable and Immutable Objects by David O'Meara (JavaRanch)
Immutable object (Wikipedia)
 
indra negi
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Thanks Anastasia and Jesper.

Got it.
 
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