опять это this

public class Solution {
    public static void main(String[] args) {
        System.out.println(new Hryvnia().getAmount());
    }
    public static abstract class Money {
        abstract Money getMoney();
        public Object getAmount() {
            return getMoney().getAmount();
        }
    }
    public static class Hryvnia extends Money {
        private double amount = 123d;
        @Override
        public Object getAmount() {
            return amount;
        }
        public Hryvnia getMoney() {
            return (Hryvnia) getAmount();
        }
    }
}

public class Solution {
    public static void main(String[] args) {
        System.out.println(new Hryvnia().getAmount());
    }
    public static abstract class Money {
        abstract Money getMoney();

        public Object getAmount() {
            return getMoney().getAmount();
        }
    }
    public static class Hryvnia extends Money {
        private double amount = 123d;
        public Hryvnia getMoney() {
            return this;
        }
        public Object getAmount() {
            return amount;
        }
    }
}

public Hryvnia getMoney() {
    return this;
}

public static void main(String[] args) {
    System.out.println(new Hryvnia().getAmount());
}