I want a example of FINAL "REGULAR" INNER CLASS. Why I want to define a final "regular" inner class?

[pedro abs]

Hello, below I elaborate an example of abstract inner class. But why I want to define a final inner class? How can I extend an inner class? That's because I'm confused. If I can't extend an inner class, why I have to define it final?


Example of abstract inner class:


The example below illustrate the use of an internal class and abstract (abstract inner class). Imagine that we have a class that represents a form with a button (MyForm) and that class should trigger an event by clicking on the button.

Thus, was declared an internal and abstract class (Events) whose abstract method must be implemented in the class that, in fact, will implement the behavior for the click of a button

class MyForm {
		private Events events;
		
		public void setEvents(Events events){
			this.events = events;
		}
		
		public abstract class Events {
			abstract void onClick();
		}
		
		public void clickOnButton(){
			events.onClick();
		}
	}
	
	
	public class OuterTest2 {
		public static void main(String args[]){
			MyForm form = new MyForm();
			
			form.setEvents(form.new Events(){
				@Override
				void onClick() {
					System.out.println("button clicked");
				}
			});
			
			form.clickOnButton();
		}
	}

I imagine that abstract and inner class is good for the sake of organization, but what about final and inner class ???

[Ankit Garg]

But why I want to define a final inner class? How can I extend an inner class? That's because I'm confused. If I can't extend an inner class, why I have to define it final?

You can extend an inner class. You just need an instance of its enclosing class to call the constructor of the inner class from the sub-class. Look at this

class Outer {
    class Inner {}
}
class Another extends Outer.Inner {
    Another() {
        new Outer().super();
    }
}

[pedro abs]

Thank you !

[pedro abs]

Sorry but one more thing about your code:

class Outer {
    class Inner {}
}
class Another extends Outer.Inner {
    Another() {
        new Outer().super();
    }
}

What is the meaning of the line
new Outer().super();


I mean I'm instantiating the superclass of Outer? Just it?

[Ankit Garg]

I mean I'm instantiating the superclass of Outer? Just it?

I can't understand what you are saying. We are instantiating the *enclosing* class of Inner class so that we can call the Inner class constructor...

[pedro abs]

Ok, I left one link to better understand.


I have the same doubt this guy.
http://stackoverflow.com/questions/2831484/java-non-static-nested-classes-and-instance-super

Thanks again