package com.baeldung.enums; public enum PizzaDeliverySystemConfiguration { INSTANCE; PizzaDeliverySystemConfiguration() { // Do the configuration initialization which // involves overriding defaults like delivery strategy } private PizzaDeliveryStrategy deliveryStrategy = PizzaDeliveryStrategy.NORMAL; public static PizzaDeliverySystemConfiguration getInstance() { return INSTANCE; } public PizzaDeliveryStrategy getDeliveryStrategy() { return deliveryStrategy; } }