In continuation to static method overriden

[Naseem Khan]

Wat will happen, If I declare static final method in super class and redefine same method in sub class...
Sub-class can define same prototype which will be a different method all together and it will also hide the super class static method.

  
class Parent {  
  static final void f() { System.out.println("parent");} // line (1)}
 
class Child19of46 extends Parent {  
  static final void f(){System.out.println("Child");} // line (2)  
 
  public static void main(String args[]){ }
} 

In above code, If I compile, It will give compilation error....
Method declare at line 1 is final.. At line 2, its a totally different method, its not overriden becoz of static declaration at line 1.

Wats the problem...

Regards

Naseem.K

[Krishna Bulusu]

hi,
final methods can not be visible to the childs classes.
In this case..the method f() is not visible to the child class...
if u remove the finla keyword from the parent class....it is nth but 'hiding' not 'overriding' b'coz f() is static...for this to happen..the method in the parent class should be visble to the child class....unless it is visible how can the compiler recognise it whether it is overriding or hiding??

plz correct me if i am wrong

krishna.

[Girish Nagaraj]

1)final methods can not be visible to the childs classes-->WRONG.

final methods are visible in the subclass as below code shows.

class Parent {

static final void f() {System.out.println("parent");} // line (1)
}

class Child19of46 extends Parent {

//static final void f(){System.out.println("Child");} // line (2)

public static void main(String args[]){

Parent p = new Child19of46();
p.f();
}
}

2)declaring method as final(instance/static) in superclass implies

a)instance method in superclass can not be overriden in subclass.
b)static method in superclass can not be hidden in subclass.

3)Method declare at line 1 is final.. At line 2, its a totally different method, its not overriden becoz of static declaration at line 1.

a)This is the case for private methods.
b)Method at line (2) is not a totally different method.

4)You are getting compile time error because you are trying to hide static final method in superclass.

[ May 15, 2006: Message edited by: Girish Nagaraj ]
[ May 15, 2006: Message edited by: Girish Nagaraj ]

[bnkiran kumar]

For static methods there is a concept of hidding not method overridding.For hidding also it is necessary to follow all conditions that we follow for method overriding like return type,type and number of parameters,exceptions in throws clause.

in your example you declared method as final,for static or non static, final methods should not be overridden.


so compilation error came.

[wise owen]

8.4.8 Inheritance, Overriding, and Hiding.