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Hello Guys I have a ques

class A { class B { B b; } } in above example B b; is a ref variable or instance ....and if it s ref variable then it point to which object & as u see i cannot created its object so what would be the benefit of this ref var

20th Jan 2020, 10:13 PM
Wasiq Abdullah
3 Réponses
+ 1
B b; // Here b is a reference to class B whereas the whole class B is like an instance variable of class A. This is a simple concept of inner classes which are non-static in your case so you have to create an instance of the outer class A and then create the instance of the inner class B unlike static where you can directly create an instance for the inner class. We generally use nested or inner classes - 1) to have more readable and maintainable code. 2) also the inner class objects can access all the data members of the class enclosing it. Here is a simple example. https://code.sololearn.com/cIT32cxCQC0k/?ref=app
21st Jan 2020, 2:00 AM
Avinesh
Avinesh - avatar
+ 3
//Java class A { class B { B b; } } public class Prg { public static void main(String[] args) { A.B ab = new A().new B(); System.out.println(ab); // A$B@7a81197d System.out.println(ab.b); // null ab.b = ab; System.out.println(ab.b ); // A$B@7a81197d } }
20th Jan 2020, 11:16 PM
zemiak