Real World Example

A Zomato-like backend is organised by feature. Each feature package exposes a small public service and hides helpers.

com.fooddelivery
├── restaurant   RestaurantService (public), MenuParser (package-private)
├── order        OrderService (public), OrderValidator (package-private)
├── delivery     DeliveryService (public), RouteCalculator (package-private)
└── common       Money, AppException

package com.fooddelivery.order;

import com.fooddelivery.common.AppException;
import com.fooddelivery.common.Money;
import com.fooddelivery.restaurant.RestaurantService;

import java.util.List;

public class OrderService {
    private final RestaurantService restaurants;
    private final OrderValidator validator = new OrderValidator();   // same package

    public OrderService(RestaurantService restaurants) {
        this.restaurants = restaurants;
    }

    public Money place(String restaurantId, List<String> itemIds) {
        if (!restaurants.isOpen(restaurantId)) {
            throw new AppException("Restaurant is closed");
        }
        validator.validate(itemIds);
        return restaurants.priceOf(restaurantId, itemIds);
    }
}