Inner classes

[Roll]

13)
Which of the following statements is true?
a) An interface can contain a nested top-level inner class.
b) An interface can contain a member inner class.
c) A member inner class can implement an interface.
d) A static method can contain a local class.
e) A static method can contain a nested top-level class.
I think its c) and d).
Why not a) because interface conatains nested toplevel classes not nested top-level inner class.
Why not b) look above for a) expl..

[Paul Salerno]

I believe the answer is A, C, and D.
Can anyone else elaborate?

[Junilu Lacar]

If the source says A is true, I would say it is badly worded. Taken as it is, I would say it's wrong: There is no such thing as a nested top-level inner class. It's either an inner class or a top-level class, not both.
You can, however, define a class as a member of an interface and the effect is the same as declaring a top-level class.
Check out the difference between the way you'd instantiate a class defined in an interface and the way you'd instantiate a true inner class:

  
class Y {
    class Z {
        public void foo() {
            System.out.println("Y.Z.foo()");
        }
    }
}

interface I {
    class X {
        public void bar() {
            System.out.println("I.X.bar()");
        }
    }
}

public Test {
    public static void main(String[] args) {
        Y.Z yz = new Y().new Z();
        yz.foo();
        I.X ix = new I.X(); // class X is really a static member of interface I
        ix.bar();
    }
}

[ February 01, 2002: Message edited by: Junilu Lacar ]

[Junilu Lacar]

Here's the where the JLS mentions Interface Member Types: http://java.sun.com/docs/books/jls/second_edition/html/interfaces.doc.html#252566

"Roll"
Please take a moment to review the JavaRanch Naming Policy. Please re-register using a Display Name that complies with the rules.
Thanks for your cooperation.
Junilu

[Paul Salerno]

Junilu,
That was an old post I dug up whilst doing a search. Roll's probably not around any more

[Junilu Lacar]

darn itchy trigger finger...
If you promise to give fair warning when reviving old posts next time I'll promise to check the dates before unholstering my Naming Policy macro. Deal?
Junilu

[Rob Ross]

Yea, but he managed to post 61 times and still never changed his name! He was either really fast or the bartenders back then were really slow.

Rob

[Marilyn de Queiroz]

The naming policy was instituted at a later date (about Jan 2001)

[Thiru Thangavelu]

so, what are the correct answers? Junilu Lacar, can you give a explanation about the each correct answer?

[Francisco A Guimaraes]

what�s the difference between options A and B? isn�t a top-level nested class a member class?
Francisco

[Jose Botella]

There is no such thing as "a nested top-level inner class." If a class is inner it cannot be top level.
"a member inner class." The members of a class include fields, methods and other classes or interfaces declared within the body of the class. Also those inherited from other classes or interfaces are members.