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Pass By Value Problem

Vijay Chandran
Ranch Hand

Joined: Jan 07, 2007
Posts: 178


Dear Friends,

When i execute this code, the output is 1 0 1.
Java uses pass-by-value. How come the values of a and c change but not the value of b?

Kindly provide your help.

Regards,
Vijay.
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19651
    
  18

Because in method g it updates the value of the parameter, not the field of the object. This is called shadowing.

Array c is also shadowed, but because that's a reference to an object, the parameter points to the same object, so the same object is modified.


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Ernest Friedman-Hill
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Joined: Jul 08, 2003
Posts: 24183
    
  34

There are two different variables named "b". One is a member variable, while the other is a parameter to the "g()" method. The parameter is changed, but the member is printed.

The value of "c" is not changed; only the contents of the array c is changed. When you pass an array, it is a reference to the array is passed by value. "Pass by value" for objects like arrays doesn't mean that the value of the array or object itself is copied; only the reference is copied.


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