छोटा प्रोजेक्ट: REST API

public class UserDto {
  private String name;
  private int age;
  // getters and setters omitted for brevity
}

import java.util.*;import org.springframework.stereotype.Service;
@Service
public class UserService {
  private List<UserDto> users = new ArrayList<>();

  public List<UserDto> getAll() { return users; }
  public void add(UserDto u) { users.add(u); }
}

import org.springframework.web.bind.annotation.*;import java.util.*;@RestController
@RequestMapping("/users")
public class UserController {
  private final UserService service;
  public UserController(UserService service) { this.service = service; }

  @GetMapping
  public List<UserDto> all() { return service.getAll(); }

  @PostMapping
  public void add(@RequestBody UserDto dto) { service.add(dto); }
}