Overriding member variables in Java ( Variable Hiding)
I am studying overriding member functions in JAVA and thought about experimenting with overriding member variables.
So, I defined classes
public class A{
public int intVal = 1;
public void identifyClass()
{
System.out.println("I am class A");
}
}
public class B extends A
{
public int intVal = 2;
public void identifyClass()
{
System.out.println("I am class B");
}
}
public class mainClass
{
public static void main(String [] args)
{
A a = new A();
B b = new B();
A aRef;
aRef = a;
System.out.println(aRef.intVal);
aRef.identifyClass();
aRef = b;
System.out.println(aRef.intVal);
aRef.identifyClass();
}
}
The output is:
1
I am class A
1
I am class B
I am not able to understand why when aRef is set to b intVal is still of class A?
When you make a variable of the same name in a subclass, that's called hiding. The resulting subclass will now actually have both properties. You can access the one from the superclass with super.var
or ((SuperClass)this).var
. The variables don't even have to be of the same type; they are just two variables sharing a name, much like two overloaded methods.
Variables are not polymorphic in Java; they do not override one another.