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Author

Dynamic assignment of an Array

Poorna Nandam
Greenhorn

Joined: Apr 01, 2009
Posts: 20
HI All,

I am new java Ranch. Can any body explain me the following code.

public class A{

private String runNow(){
return "High";
}

static class B extends A{
public String runNow(){
return "Low";
}
}

public static void main(String args[]){
A[] a=new B[]{new B(),new C()};
for(A aa:a)
System.out.print(aa.runNow()+" ");
}

}


class C extends A.B{

public String runNow(){
return "Out";
}

}
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 38509
    
  23
Please use the code button; it makes your code easier to read.

We don't simply give out answers, so it would help if you answer these three questions:
What output did you expect? What output did you get? Have you any ideas why?
Poorna Nandam
Greenhorn

Joined: Apr 01, 2009
Posts: 20
Thank a lot............................

Poorna Nandam
Greenhorn

Joined: Apr 01, 2009
Posts: 20


As you told me that , i want to know the above Array assignment.
Thanks in advance.


salvin francis
Ranch Hand

Joined: Jan 12, 2009
Posts: 928

I am going to give you hints:



can be written as:




Actually even the class cast is not important in this case, but thats my way of saying that it will behave like "A"

My Website: [Salvin.in] Cool your mind:[Salvin.in/painting] My Sally:[Salvin.in/sally]
Poorna Nandam
Greenhorn

Joined: Apr 01, 2009
Posts: 20
Thank you salvin,


BR
Poorna
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 38509
    
  23
That was a useful hint. Now, remembering the question is really about inheritance not arrays, what do you think the output would be?
Poorna Nandam
Greenhorn

Joined: Apr 01, 2009
Posts: 20
Output would be



Thank you,
Poorna
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 38509
    
  23
Have you tried it? That is what happened, so your suggestion is correct.
Now please explain why you are not using polymorphism when you are calling instance methods.
 
With a little knowledge, a cast iron skillet is non-stick and lasts a lifetime.
 
subject: Dynamic assignment of an Array