Question

Here is an example :

class Parent {
    protected int A;

    public void displayA() {
        System.out.println(A);
    }
}

class Child extends Parent {
    protected static int A=2;
}

Child intance = new Child();
intance.displayA();

=> return null !!!

What is the way to retrieve the child attribute from parent method ?

Thank you 🙂

Answer 1

In your instance if you use your Child class constructor to set the value of A rather than redeclaring the variable then the parent class should be able to get the value.

The problem with the instance above is that you are redeclaring the variable in your sub class rather than just altering the value of the variable in your superclass.

Is there a reason that you have the child variable declared as static? If you only need the value of that class variable then you can reference it directly. However a neater way to have the potential for multiple subclasses to set the variable value and it be used by the super class is to have the child classes set the value you want and then have the super class reference that variable (possibly using a getter) that the subclass has set the value of.