how can we access a method from sub class from its super class?

[kiran kumar]

Hi,
class A{
public void methodA(){}
}

class B extends A {
public void methodA(){}
}

class C extends B {
public void methodA(){}
public static void main(String args[]){

// How can we call methodA in class A without creating instances how can we call.

}

}

[Paul Sturrock]

Sounds like a homework question. What do you think the answer is?

[Rob Spoor]

This is really a beginner question, so that's where this thread is moving.

[Ronald Schild]

Have a look at the 'super' keyword, you may find what you're looking for.

[haripriya vedula]

A subclass can call a constructor method defined by its superclass using keyword super..

[Campbell Ritchie]

Do you really mean to access a subclass member from the superclass? You can't. Simple.

Imagine you have a "sub" keyword.

public class A
{
  public void method()
  {
     . . .
  }
}
 
public class B extends A
{
  @Override
  public void method() . . .
}
 
public class C extends A
{
  @Override
  public void method() . . .
}

Now, how could you write code in class A which could reach the method in a subclass with sub.method(). How can the compiler tell whether there are any subclasses at all, or whether you mean B or C? You could possibly write in class A, A b = new B(); but I am sure that's not what you mean.

[Ilja Preuss]

Another interpretation would be that you *can* - through polymorphism. If the superclass declares the method, and the subclass implements/overrides it, the superclass can call it. (An example for this is the Template Method design pattern.)

[Peter Chase]

In some circumstances, you could cast "this" to the subclass, if you know that the current object is really an instance of a particular subclass. However, this is very bad programming practice; a superclass should never know about its subclasses.

[Mohamed Manas]

Originally posted by rahul dravid:
class C extends B {
public void methodA(){}
public static void main(String args[]){

// How can we call methodA in class A without creating instances how can we call.

}

}

I think Rahul wants to access methodA in classA from classC.
In this case although we can't directly call a overridden method from a super class, following trick will do the job.

class classA {
public void run()
{
System.out.println("Running class A");
}
}
 
class classB extends classA {
public void run()
{
System.out.println("Running class B");
}
 
public void trickyMethod()
{
[B]super.run();[/B]
}
}
 
class classC extends classB {
public void run()
{
System.out.println("Running class C");
}
 
public static void main(String[] args)
{
classC c = new classC();
c.run2();
}
 
public void run2()
{
[B]super.trickyMethod();[/B]
}
}

I hope this helps.