Code call (Inheritance)

[Wu Wen]

class A {  public void perform_work(){}  }
class B extends A {  public void perform_work(){}  }
class C extends B {  public void perform_work(){}  }

The question is How can you let perform_work() method of A to be called from an instance method in C?
And the right answer is There is no way to go more than one level up for methods.

I thought I could use ( (A) this ).perform_work( ) in C to call A's perform_work(), but I got StackOverflowError.
Can anyone explains me why it is not working?

Thanks

[Tomasz Sochanski]

Wu Wen wrote:
I thought I could use ( (A) this ).perform_work( ) in C to call A's perform_work(), but I got StackOverflowError.
Can anyone explains me why it is not working?

Wu - please provide your code here, there are no exceptions runnig ie. this code:

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

public class C extends B {
	public static void main(String[] args) {
		C c = new C();
		((A) c).perform_work();
	}
	public void perform_work(){} 
}

[Wu Wen]

Here it is

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

public class C extends B {
	public void perform_work() {
		((A) this).perform_work();
	}

	public static void main(String args[]) {
		C c = new C();
		c.perform_work();
	}
}

[Matthew Brown]

You can't do what you're trying to do. You can cast to a superclass, but polymorphism means that you'll still be calling the version of perform_work() in the subclass. Which means that in your code the method is calling itself, which leads to a stack overflow.

The only way to call the superclass method is via super.perform_work(), but that only calls the version in the immediate superclass.

[Wu Wen]

Matthew Brown wrote:You can't do what you're trying to do. You can cast to a superclass, but polymorphism means that you'll still be calling the version of perform_work() in the subclass. Which means that in your code the method is calling itself, which leads to a stack overflow.

The only way to call the superclass method is via super.perform_work(), but that only calls the version in the immediate superclass.

I get it. Thank you.