1. Model Classes:

• Encapsulation and Data Integrity: Consider using immutable objects where possible to avoid accidental modification of objects. This is particularly useful for entities like Location and other value objects.
• Annotations: In production, use annotations like @Entity, @Table, and others for database mapping.
• Enums: Use enums for fields that represent a state or fixed set of values, e.g., status in Ride and Payment classes.
• ID Generation: Utilize annotations for auto-generating unique identifiers, like @Id and @GeneratedValue.

public enum Status {
    PENDING, ACTIVE, COMPLETED, CANCELLED
}

2. Service Interfaces:

• Parameter Validation: Validate parameters to prevent invalid data from propagating through the system.
• Exception Handling: Define and document custom exceptions that could arise from business logic errors.

3. Example Implementations:

UserServiceImpl Lack of Implementation Detail: The method bodies are missing. Implement simple logic first, even if it’s just stubs simulating the behavior.

public class UserServiceImpl implements UserService {
    private Map<String, User> userStore = new HashMap<>();

    @Override
    public User registerUer(String name, String contact) {
        String userId = UUID.randomUUID().toString(); // Generates a unique ID
        User newUser = new User(userId, name, contact);
        userStore.put(userId, newUser);
        return newUser;
    }

    @Override
    public User getUser(String userId) {
        return userStore.get(userId);
    }
}

4. API Endpoints (Controllers):

• Dependency Injection: Use @Autowired to inject the UserService in the UserController.
• Input Validation: Validate user inputs immediately in controller methods to ensure data integrity.
• Error Handling: Add exception handlers using @ControllerAdvice to manage exceptions and return proper HTTP status codes.

@RestController
@RequestMapping("/users")
public class UserController {
    @Autowired
    private UserService userService;

    @PostMapping("/auth")
    public ResponseEntity<User> registerUser(@RequestBody User user) {
        if (user.getName() == null || user.getContact() == null) {
            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
        }
        User newUser = userService.registerUser(user.getName(), user.getContact());
        return new ResponseEntity<>(newUser, HttpStatus.CREATED);
    }
}

5. Database Integration:

• ORM Mapping: Ensure that each model class is mapped correctly using JPA annotations to ensure it corresponds to the intended database structure.
• Database Design: Consider relationships between entities such as One-To-Many or Many-To-One, especially between User,