Six endpoints, and what each publishes

import java.util.*;

/**
 * Challenge: six endpoints from one service. All six return or accept an
 * entity somewhere. They fail in four different ways.
 */
public class Starter {

    // ── 1 ─────────────────────────────────────────────────────────────────
    //   @GetMapping("/users/{id}")
    //   public User get(@PathVariable Long id) { return repo.findById(id).orElseThrow(); }
    //   User has: id, email, displayName, passwordHash, lastLoginIp, deleted

    // ── 2 ─────────────────────────────────────────────────────────────────
    //   @PostMapping("/users")
    //   public User create(@RequestBody User user) { return repo.save(user); }

    // ── 3 ─────────────────────────────────────────────────────────────────
    //   @GetMapping("/authors/{id}")
    //   public Author get(...)          // Author has List<Book>, Book has Author

    // ── 4 ─────────────────────────────────────────────────────────────────
    //   @GetMapping("/orders/{id}")
    //   public OrderResponse get(@PathVariable Long id) {
    //       return mapper.toResponse(orderService.find(id));   // service is @Transactional
    //   }

    // ── 5 ─────────────────────────────────────────────────────────────────
    //   @GetMapping("/books/{id}")
    //   public Book get(...)            // Book.author is annotated @JsonIgnore

    // ── 6 ─────────────────────────────────────────────────────────────────
    //   @GetMapping("/orders")
    //   public List<Order> list()       // Order.lines is LAZY, open-in-view is default

    public static void main(String[] args) {

        // TODO 1: classify each endpoint by which problem it has — disclosure,
        // schema coupling, recursion, or queries during serialisation. Some
        // have more than one.

        // TODO 2: for endpoint 1, list every field a client can see today.
        // Then say what happens when someone adds a `mfa_secret` column.

        // TODO 3: for endpoint 2, list every field a caller can SET. Which one
        // turns a create into an update, and against which row?

        // TODO 4: endpoint 4 has a DTO and still fails. Explain where the
        // mapping happens and why that undoes the DTO. Move it.

        // TODO 5: endpoint 5 is "fixed". Say what a consumer who needs the
        // author from a book must now do, and who ends up paying for that fix.

        // TODO 6: endpoint 6 works in production and is slow. Count the
        // queries for a page of 50 orders, and say in which phase they happen.
        // Then say what changes if open-in-view is turned off — the answer is
        // not "it gets faster".

        // TODO 7: one change fixes five of these six. Name it, name the one it
        // does not fix, and say what that one needs instead.
    }
}