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Doubt with Inheritence

 
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source MinQ-Q35

For the following code:
class Super
{ int index = 5;
public void printVal()
{ System.out.println( "Super" );
}
}
class Sub extends Super
{ int index = 2;
public void printVal()
{ System.out.println( "Sub" );
}
}
public class Runner
{ public static void main( String argv[] )
{ Super sup = new Sub();
System.out.print( sup.index + "," );
sup.printVal();
}
}
What will be printed to standard output?
a) The code will not compile.
b) The code compiles and "5, Super" is printed to standard output.
c) The code compiles and "5, Sub" is printed to standard output.
d) The code compiles and "2, Super" is printed to standard output.
e) The code compiles and "2, Sub" is printed to standard output.
f) The code compiles, but throws an exception.
Ans: C

How??

Regards,
Gitesh
 
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Methods are polymorphic, but member variables are not.

You have a variable 'sup'. The type of the variable is Super, but it actually refers to a Sub object. Because of polymorphism, if you call a method on 'sup', Java will look for the method in class Sub first. But it doesn't work in the same way for member variables; there, Java only looks at the type of the variable (which is Super).
 
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Ok well!!

again i think the same concept arrives
you must see this statement as below...




here sup is arefernce variable of Super
class but it is object of Sub class hence
it calls the Sub class method and prints
"Sub"

later sup.index...here since refernce variable
of super class is used so it prints the instance variable
of super class.!!!
 
Gitesh Ramchandani
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Thanks for help, Doubt cleared.
 
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