Regarding inner classes

[Pradeep Kumar]

Hi,
I am preparing for the SCJP but i fount is interesing while i observed some scenarios. I am curious about these things and want to get my doubts cleared.Here are the some observations i could make out.

1. What is the sigmificance of a regular inner class which is abstract or an interface.
2. If i have a inner class which is abstract or an interface what is its significance outside the class, For ex:

public class Test {
public abstract class Inner{
}
}
class Test1 extends Test{
Test.Inner ob = new Test().new Inner();
}
Can i instantiate the inner class somehow in Test1.If yes what will be the syntax.

[dhwani mathur]

Yes i think you can instantiate inner class!!!

[ahmed yehia]

Same rules apply as top level classes, you cannot instantiate abstract classes.

[Burkhard Hassel]

Yes, but you could make an anonymous class of the abstract class, e.g.

class Main {
public static void main(String[] args) {
System.out.println(new Test().new Test1().ob);
}
}
 
class Test {
public abstract class Inner {
}
 
class Test1 extends Test {
// Test.Inner ob = new Test().new Inner(); //no
Test.Inner ob = new Test().new Inner() {
// anonymous class
};
}
}

output is something like
Test$1@1f6a7b9

Then you have an anonymous inner class of an abstract inner class...

(I removed the public modifiers to have them all in one file)



Yours,
Bu.