Java “trick”, redefining daughter class member

Question

I\'m training for a Java exam, and I\'ve come across something I don\'t understand in last year subject. Here is the code

class Mother {
    int var = 2;

    in         


        

Answer 1

Focus on these lines:

Mother m;
 m = new Daughter();
 System.out.println(m.var);
 System.out.println(m.getVar());

You are constructing a Daughter object, but you are treating it like it's base class Mother. So when you access m.var you are accessing the base class variable var. Meanwhile when you call a method, even if you are referring to the base class reference, the overrided method is called. It's a different behavior for methods and fields.. Fields reference cannot be overrided.