is it dynamic binding?

[saikrishna cinux]

hey here is one program


abstract class A
{

abstract void abc();
void xyz(){}
}


class B extends A
{

abstract void abc(){}

}

class Test{
public static void main(String args[])
{
B b =new B();

b.abc();
b.xyz();//DYNAMIC BINDING
}
}



so yesterday one senior software is saying that by calling b.xyz(); the concept is dynamic binding

but i told him that it is a inheritence concept but he is not satisfied at my answer


how can it be a dynamic binding here when i am calling the method b.xyz(); it will be checked at compile time ot at runtime am i right ???


please tell me your views

[Ajay Singh]

A b =new B();

b.abc(); // IS dynamic binding

[Ilja Preuss]

The language *is* using dynamic binding to call the method, even though it wouldn't be necessary in this special case.

[Jesper de Jong]

so yesterday one senior software is saying that by calling b.xyz(); the concept is dynamic binding

but i told him that it is a inheritence concept but he is not satisfied at my answer

You make it sound as if these are two mutually exclusive concepts. They are not. Ofcourse your example code involves inheritance. Java uses dynamic binding to find out which version of a method to call - the version in the superclass or the version in the subclass.

If you do this:

B object = new B();
object.xyz();

then dynamic binding is not really necessary, because the compile-time type of the object is the same as the dynamic (runtime) type of the object. However, if you do this:

A object = new B();
object.xyz();

then the compile-time type of the object (A) is different from the dynamic type (B) - and Java has to determine at runtime (not at compile time) that it should call method xyz() in class B instead of class A. That's dynamic binding.