The result of instance variable of inheritance.

[Sam Sunamin]

What's the result of the following code?

public class Question10 {

public A getObject() {
return new A();
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Question10 q10 = new SubQuestion10();
System.out.println(q10.getObject()); //line 10
System.out.println(q10.getObject().x); //line 11
}

}

class SubQuestion10 extends Question10{
public B getObject() {
return new B();
}
}

class A{
int x=5;
}

class B extends A{
int x=6;
}

When I run the code, I got the result as:
B@1372a1a
5


My question is why line 11's result is not 6, but 5.
But the result of line 10 is B@1372a1a, not A@1372a1a

[Chandra Bhatt]

Hi Sam,

Try this modified code and understand what exactly is happening...

 
public class Question10 {
 
public A getObject() {
return new A();
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Question10 q10 = new SubQuestion10();
System.out.println(q10.getObject()); //line 10
A a1 = q10.getObject();
B b1 = (B)q10.getObject();

System.out.println(a1.x);
System.out.println(b1.x); //line 11
}
}
 
class SubQuestion10 extends Question10 {
public B getObject() {
return new B();
}
}
 
class A {

int x=5;
}
 
class B extends A{

int x=6;
}
 
"Member varaibles are not overridden, they are shadowed", they are called using the reference variable, dont expect any polymorphic behavior from this...
 
Thanks and Regards,
cmbhatt