Constructor

[Puja S]

Hi,

A class which has all its constructors declared as private

1. Cannot be instantiated by any other class.
2. Cannot be extended.
3. Both i and ii.
4. has to be declared final.

What should be the correct options? I thought the answer was 1 but it said that it was 3.

Thanks

[Pradeep bhatt]

A subclass constructor by default call no arg constructor of superclass but since superclass constructor is private it wont work.

[Rajasekar Elango]

Yes, You can't extend a class that has declared all its constructors as private.

Because any class extending it should call its super class constructor and this will cause error as sub class cannot access private members of super class.

Look at .Corey Tips for more explanation..

Thanks,
Raja

[shri mon]

I think The correct answer is 1 and 3.

How can the subclass call the private member of the super class.

[Surendra Kumar]

The correct answer is 2.

you can instaniate the class by having a static method which makes a call to private constructor(just like singleton pattern).

[Pradeep bhatt]

Originally posted by Surendra Kumar:
The correct answer is 2.

you can instaniate the class by having a static method which makes a call to private constructor(just like singleton pattern).

As per you statment, 1 is also a answer. You forgot to metion it.
[ January 13, 2005: Message edited by: Pradeep Bhat ]

[Surendra Kumar]

thanks for correcting it

[Barry Gaunt]

Originally posted by shri mon:
I think The correct answer is 1 and 3.

Um, interesting choice of The correct answer.

[Puja S]

Thanks to all..... so the answer is 3

[Jack Zhou]

You can still have an inner class extends an outer class with all contructor being private. So the answser is 1. Is it a bad question?

[Barry Gaunt]

Originally posted by Jack Zhou:
You can still have an inner class extends an outer class with all contructor being private. So the answser is 1. Is it a bad question?

That's a counter!

public class Mine
{
    private Mine(){};
    class Inner extends Mine {
        Mine mine;
        Mine getYours() {
        mine = new Mine();
        return mine;
        }
    }
    
    public static void main(String[] args)
    {
        Inner inner = new Mine().new Inner();
        Mine mine = inner.getYours();
    }
 
}
  

[Barry Gaunt]

I guess they were not thinking about that possibility.

[Jin chengong]

who can tell me the putting out ,and tell me exactly?

[Jesper de Jong]

Puja S, please check your private messages. You can see them by clicking My Private Messages.