How to instantiate multiple nested non-static inner classes - java

Question

I have the following piece of code:

public class InnerClassStuff {
   public class A{
       public class AA{}
    }
}

my question is how can I instantitae an AA object?

I've tried the following but it won't compile:

public static void main(String[] args){
   InnerClassStuff object = new InnerClassStuff();
   A a = object.new A();
   AA aa = object.a.new AA(); //error
}

Masudul · Accepted Answer · 2015-04-09T05:35:15.353

1

To instantiate an inner class, you must first instantiate the outer class. So, you can't declare A a= .., you need wrapped it with outer class like below:

InnerClassStuff object = new InnerClassStuff();
InnerClassStuff.A.AA a = object.new A().new AA();

Or,

InnerClassStuff object = new InnerClassStuff();
InnerClassStuff.A a = object.new A();
InnerClassStuff.A.AA aa = a.new AA();

edited Apr 09 '15 at 05:35

answered Apr 09 '15 at 05:25

Masudul

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Or replace the last line of the original code with `AA aa = a.new AA();` – redge Apr 09 '15 at 05:28
I tried using AA aa = a.new AA(); but it gave me an error saying "AA cannot be resolved to a type". I am using eclipse by the way. – Some_Tasty_Donuts Apr 09 '15 at 05:32
@JerryJia, You can't directly use Inner class. You should wrapped it with outer class. – Masudul Apr 09 '15 at 05:36

score 0 · Answer 2 · answered Apr 09 '15 at 06:06

To access the class you have to use The outer class name, only by doing so you can have reference variable of inner class. eg:

InnerClassStuff object = new InnerClassStuff();
InnerClassStuff.A a = object.new A();
InnerClassStuff.A.AA aa = a.new AA();

How to instantiate multiple nested non-static inner classes - java

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