A question on object !!!

[Swosti Dipan Pal]

Suppose there is a class called Animal. Dog extends the Animal class. Can anyone explains what is the use of this kind of object ?

Animal a=new Dog2();

Cheers,
-Biswa

[dai jiansong]

I think :
first "new Dog2();" means creat a new object of the subclass-Dog2 with its constructers:
second "Animal a" a is the new object's reference ,its cast is Animal
third "=" is evaluation and upcast

[Chandra Sagi]

By creating a Dog2() object using

Animal a = new Dog2();

We are saying that the Dog2() object behaves like an Animal. The advantage would may be later you could change the object Dog2() to some object Dog3 () and refer it as

Animal a = new Dog3 ();

still the code using "Animal a" need not be changed. We are ensuring here that both Dog2() and Dog3() behave like animal.

Thanks
Chandu