static final methods

[faisal usmani]

hi,

public static final abc() is a valid method I cannot understand what signify to makes static method a final .Anyhow a static method cannot be overridden.

Can anyone explain why we declare a static method final.


thanx in advance

[Jeff Albertson]

class A {
    public static void isNotFinal() {}
    public static final void isFinal() {}
}
 
class B extends A {
    public static void isNotFinal() {} //ok
    public static void isFinal() {} //error!
}

It stops you from declaring a static method with the same name and parameter types in a derived class. Why do this? I don't see the need for it and I've never seen it used. Does anyone do this?

[faisal usmani]

no idea !!! :roll:


There is no duty more obligatory than the repayment of kindness.
[ May 11, 2006: Message edited by: faisal usmani ]

[Jeff Albertson]

This might be a reason for someone to make a static method final:

class A {
    public static void f() {
        System.out.println("A.f");
    }
}
 
public class B extends A {
    /*
    public static void f() {
        System.out.println("B.f");
    }
    */
 
    public static void main(String[] args) {
        f();
    }
}

The call to f() im main resolves to A's version of f, but when you uncomment B's version of f, it hides A's f. I'm not worried about this because I think I'm careful when I invoke a static method to use the name of the class that introduces it.
[ May 11, 2006: Message edited by: Jeff Albertson ]