reg overriding

[swapna hyderabad]

I have a super/sub class as below

 
public class super(){
 
public void display(){
 
...super implementation
....
}
}
 
public class sub(){
 
public void display(){
 
...sub implemation
....
}
 
//main class method
public class mainclass(){
 
p.s.v.m(s a[]){
 
super s=new sub();
 
s.display();// 1
 
}}

the 1 line will call the sub class method but I want it should call only super class method with out creating object of super class........

Please any suggestions.....solution.....help:-)
[ November 20, 2008: Message edited by: Martijn Verburg ]

[Henry Wong]

the 1 line wiill call the sub class method but i want it shoud call only super class method with out creating object of super class........

It is *not* creating object of super class -- it is the sub class that is being created. Remember a sub class IS-A super class. It can be used where the super class is used.

And no, you can't decide that the sub class is no longer a sub class. The overridden version will be called because it IS-A sub class.

Henry

[swapna hyderabad]

My question is ::

super s=new sub();

s.dispaly();//1

This line 1 shoud call the super cls method only...means i want to be excute super cls method implementaion..is it possible or not?

[Campbell Ritchie]

You can call super.display() but only from inside a subclass object (ie not static).
You cannot write "super s"; that will always throw a compiler error because you have the keyword super out of its correct context.

[swapna hyderabad]

You can call super.display() but only from inside a subclass object (ie not static).

thanks for reply.....
but i want only it shoud execute super cls method,i.e i dont want to excute sub class implementation at all......any solution?

[Campbell Ritchie]

You can only call the superclass implementation from inside the subclass. If you want the superclass implementation from outside that, you have to make sure your runtime type of the object is a superclass type. Two possible solutions I can think of:

Superclass sp = new Superclass(foo, foofoo);
. . .
sp.baar();

Superclass sub = new Subclass(foo, foofoo);
. . .
((Superclass) sub).baar();

What you want to learn is object-oriented programming, not a particular language.
Using a superclass method which has been overridden in the object you are using breaches the customs of inheritance and polymorphism; it ceases to be true object-oriented programming.

[swapna hyderabad]

Thanks...Campbell ...you solved my problem........THANKS AGAIN

[Campbell Ritchie]

You're welcome