How to use Abstract inner classes ?

[munna next]

In the belwo code I know I can not use new Inner() becuase it's an abstract inner class. But I am not able to visualize where and how I can use abstract inner class ?

 
class Upper{
    int i=30;
    int dothis(){
        Inner I = new Inner();
        return I.returni();
    }
    protected abstract class Inner{
        int returni(){return i;}
    }
}
 
class Testing{
    public static void main(String args[]){
        Upper.Inner ui = new Upper().new Inner();
        System.out.println(ui.returni());
        Upper u = new Upper();
        System.out.println(u.dothis());
    }
}

(

tags added)
[ July 11, 2006: Message edited by: Barry Gaunt ]

[Keith Lynn]

Since the inner class is protected, you can create other inner classes in this class definition or in any subclass of this class definition that extend the abstract inner class and give concrete implementations to its abstract methods.

[munna next]

Thaks Keith for reply. What happens if inner class is public ? I can use only thru sub class of the inner class ? I can not use this abstract inner class in enclosing class (Upper) ? tahnks for reply.