How can I get a variable of a class from an abstract class?

Question

if I have an abstract class and a class that extends it, how can I get variable of the class that extends it to the class that is extended, something like this:

abstract class A {
    void getVariable () {
        //get *variable* from class B and print it out
    }
}

class B extends A {
    int variable = 5;
}

Answer 1

You cannot access variable field from child class directly but you can do like this

abstract class A {
   abstract int getVariable ();

   void anotherMethod() {

       System.out.println("Variable from child: " + getVariable());
   }
}

class B extends A {
    int variable = 5;

    @Override
    int getVariable() {
        return variable;
    }
}

Answer 2

Forget about variables: What you might inherit and override is behaviours (=methods). Try this:

abstract class A {
    protected abstract int getVariable ();
}

class B extends A {
    private int variable = 5;
    protected int getVariable ()
    {
        return variable;
    }
}   

class C extends A {
    protected int getVariable ()
    {
        return 0; // This class might decide not to define its own variable.
    }
}

Answer 3

variable is only known to class B . Its superclass A has no knowledge of it. If you move variable to the superclass A and don't mark it private , then you can access it from B .