was löst denn hier einen stackoverflow aus?

public class Solution { public static void main(String[] args) { System.out.println(new Euro().getAmount()); } public static abstract class Money { abstract Money getMoney(); public Object getAmount() { return getMoney().getAmount(); } } // Code unten einfügen public static class Euro extends Money { private double amount = 123d; public Euro getMoney() { return this; } // public Object getAmount(){ <-- was passiert hier? wie verhindert das den overflow? return amount; } } }