static methods-overridden

[mad dy]

hi,

Static methods can't be overridden but they can be redefined (from K&B)
class Animal {
static void doStuff() {
System.out.print("a ");
}
}
class Dog extends Animal {
static void dostuff() { // it's a redefinition, not an override
System.out.print("d ");
}
public static void main(String [] args) {
Animal [] a = {new Animal(), new Dog(), new Animal()};
for(int x = 0; x < a.length; x++)
a[x].doStuff(); // invoke the static method
}
}

in this how to recognise tht dostuff() is redefined??

[Keith Lynn]

Because it is declared static, it is hidden and not overridden.

[Shaan Shar]

Maddy,

Exactly I don't knwo what you really want to know???

But if you will run this class.

You will understand the logic.

Actually What happens in the static method.

The real thing which matters is Class Reference, although you have overrided the method but you are calling method still with super class reference. that's why it is calling super class method.

That's it.

[mad dy]

Hi,

when I compi led and run this program i got o/p "a a a"

wht my question exactly is by seeing the code it looks like overriding the method dostuff in subclass Dog...
but actually it is redefining it..
I'm not able to understand the difference b/w them

[Keith Lynn]

You will see the difference if you remove the keyword static from the definitions.

[swarupa patil]

Hi Mad dy
For your example the answer is correct.
The reason behind is STATIC methods cannot be overridden
but we can achive this.When we compile the program
with static methods the compiler resolves at compile time
that is it calls the super class static method.
so when you try to execute the method on
Super class reference variable using subclass object .
The only super class static method execute.

[vidya sagar]

More Stuffs

[mad dy]

Thanks All,

Now I got the clear Idea.

As the static method of Super class is hidden, so it is not inherited to the Sub Class.
So there is no issue of overridding the super class static method in Sub class,
and the sub class will treat its static method as it's own method...

Am I Right???

[Andy Morris]

It's not overiding since static methods only exist in the class they are defined in. The fact a subclass has a static method with the same name is pretty much irrelevant.

When coding it is recommended to refer to static methods by their class and not via an instance variable (e.g MyClass.doStaticStuff() and not myIntance.doStaticStuff()), which would clear up any confusion about which static method will be called. In the exam if you just look at the type the reference is referring to and not what class initialised it, you shouldn't have any confusion.

[Revathi Velu]

Isn't the dostuff in the Dog class completely different method because of the lowercase s ???

[Naseem Khan]

Revathi you are right...

Its not redefinition, rather its a altogether new method.

I think he has done typo mistake.

If you use this line...

a[x].dostuff(); // invoke the static method

instead of

a[x].doStuff(); // invoke the static method

It won't compile. Compiler will complain dostuff method not defined in Animal class. Remember java is case sensitive.


Regards


Naseem

[Nilesh Patel]

is possible to access static method and variable using class object of this method and classs OR just using Class Name...

[Atul Sawant]

^^Hello all,

This is my first post.

Yes, you can call a static method or class variable using the instance of the class where these static method or class variable are defined.

However, we cannot call a non-static method or class variable using a class name.

Please share your inputs on these if you have one.