Why variables are not behaving as same as method while Overriding.? [duplicate]

Question

Generally Overriding is the concept of Re-defining the meaning of the member in the sub class.Why variables are not behaving like methods while Overriding in java ?
For instance:

class Base {

    int a = 10;

    void display() {
        System.out.println("Inside Base :");
    }
}

class Derived extends Base {

    int a = 99;

    @Override
    // method overriding
    void display() {
        System.out.println("Inside Derived :");
    }
}

public class NewClass {

    public static void main(String... a) {
        Derived d = new Derived();
        Base b = d;
        b.display(); // Dynamic method dispatch
        System.out.println("a=" + b.a);
    }
}

Since data member a is package access specified, it is also available to the Derived class. But generally while calling the overridden method using the base class reference, the method that is redefined in derived class is called (Dynamic method dispatch)..but it is not the same for the variable..why.?

EXPECTED OUTPUT

Inside Derived :
a=99

OBTAINED OUTPUT:

Inside Derived :
a=10

Prints 10 - why the variable does not behave similar to method in the derived class?
Why the variables are not allowed to be overridden in the sub class?

Answer 1

You typed b as an instance of Base. So when the compiler needs to resolve b.a, it looks to the definition of Base for the meaning of b.a. There is no polymorphism for instance fields.