@Component, @Service, @Repository, @Controller in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a Spring component class.

Spring Boot

@[1]
public class MyComponent {
}

Drag options to blanks, or click blank then click option'

AController

BService

CRepository

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service or @Repository when the class is a general component.

Forgetting the @Component annotation causes Spring not to detect the class.

The @Component annotation marks a class as a Spring component for dependency injection.

2fill in blank

medium

Complete the code to declare a service class in Spring Boot.

Spring Boot

@[1]
public class UserService {
}

Drag options to blanks, or click blank then click option'

AController

BService

CRepository

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component instead of @Service for service classes.

Confusing @Service with @Repository or @Controller.

The @Service annotation marks a class as a service layer component, typically holding business logic.

3fill in blank

hard

Fix the error in the annotation to mark a data access class.

Spring Boot

@[1]
public class UserRepository {
}

Drag options to blanks, or click blank then click option'

AComponent

BService

CRepository

DController

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service or @Component instead of @Repository for data access classes.

Not annotating the repository class causes Spring not to manage it.

The @Repository annotation marks a class as a data access component, handling database operations.

4fill in blank

hard

Complete the code to declare a Spring MVC controller class with a request mapping.

Spring Boot

@[1]
@RequestMapping("/users")
public class UserController {
    @GetMapping
    public String listUsers() {
        return "userList";
    }
}

Drag options to blanks, or click blank then click option'

AController

BService

CComponent

DRepository

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component or @Service instead of @Controller for web controllers.

Forgetting @Controller causes Spring MVC not to detect the controller.

The @Controller annotation marks a class as a Spring MVC controller to handle web requests.

5fill in blank

hard

Fill all three blanks to complete a Spring Boot REST controller with service injection.

Spring Boot

@[1]
public class ProductController {

    private final ProductService productService;

    public ProductController([2] productService) {
        this.productService = productService;
    }

    @GetMapping("/products")
    public List<Product> getAllProducts() {
        return productService.[3]();
    }
}

Drag options to blanks, or click blank then click option'

ARestController

BProductService

CgetProducts

DService

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Controller instead of @RestController for REST APIs.

Passing the wrong type in constructor parameter.

Calling a non-existent method on the service.

@RestController marks the class as a REST controller.
The constructor parameter must be the service type ProductService.
The method called on the service to get products is getProducts().