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Why the o/p is not what it is expected ?

faisal usmani
Ranch Hand

Joined: Jan 14, 2006
Posts: 139
Why output is (10 dervied) and not (20 derived)???


class Par
{
public static void main(String args[])
{
A z = new B();
System.out.println(z.a);
z.display();
}
}


class A
{
int a=10;


void display()
{
System.out.println("base");
}
}

class B extends A
{
int a=20;


void display()
{
System.out.println("derived");
}
}

output::
10
derived
Ernest Friedman-Hill
author and iconoclast
Marshal

Joined: Jul 08, 2003
Posts: 24183
    
  34

Because variables aren't polymorphic the way methods are. You can't "override a variable". In main, you've got a reference to class A, and you ask for the "a" variable, so you get the "a" variable of class A. There's no special relationship between the two "a" variables as there is between the two "display" methods.


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