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Home » Java Q&A » Core Java

Objects and reference variables of different types

Submitted by vabbs on Thu, 12/13/2012 - 00:54.
Tags:

//for example only
class A
{}
class B extends A
{
public static void main (String [] args)
{
  A a1 = new A();
  A a2 = new B();  //my doubt lies here
  System.out.println(a1);
  System.out.println(a2);
}
}

When it is declared as "A a1 = new A();", object is created to class A and 'a1' refers to the newly created object.

But, when it is declared as "A a2 = new B();", what does it imply? I am confused why should a class B object be referred by reference variable of A ?

I request to help me making this concept clear, please.