//file A.java
package p1;
public class A{
protected int i = 10;
public int getI(){
return i;
}}
// file B.java
package p2;
import p1.*;
public class B extends p1.A{
public void process(A a){
a.i = a.i * 2;}
public static void main(String[] args){
A a = new B();
B b = new B();
b.process(a);
System.out.println( a.getI() );
}}
This code fails to compile ..Its unable to access i.
Why is it? Please help
> But Class A is public and i variable is protected,$
> that means i can be accessed in a class within the
> package and also by any subclass of A.
> So why the error? I did not quite get it
> !!!!!!!!!!!!!!
I don't know how to explain that, but your approach is wrong anyway. public void process(A a) {
a.i = a.i * 2;
}
You shouldn't have one A take another A as an arg to process it. The A should just process itself. (And I know this is a B, but all Bs are As).
public void process() {
i *= 2;
}
This will probably work as far as the protected member goes too.
Also, since you're importing p1.*, you can just say extends A instead of extends p1.A.
> But Class A is public and i variable is protected,
> that means i can be accessed in a class within the
> package and also by any subclass of A.
> So why the error? I did not quite get it
> !!!!!!!!!!!!!!
B can access its own 'i' member (or 'this.i', maybe even referenced as 'super.i'). That's not what you're doing. You're trying to access the 'i' member of another object instance.
