@Autowired for dependency injection in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to inject the service using @Autowired.

Spring Boot

public class UserController {
    @[1]
    private UserService userService;
}

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

AAutowired

BInject

CService

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Inject instead of @Autowired in Spring Boot without proper configuration.

Forgetting the @Autowired annotation and manually instantiating the service.

The @Autowired annotation tells Spring to inject the UserService dependency automatically.

2fill in blank

medium

Complete the code to inject the repository via constructor with @Autowired.

Spring Boot

public class ProductService {
    private final ProductRepository productRepository;

    @[1]
    public ProductService(ProductRepository productRepository) {
        this.productRepository = productRepository;
    }
}

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

AAutowired

BInject

CService

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Not annotating the constructor and expecting Spring to inject dependencies automatically.

Using @Inject without proper configuration in Spring Boot.

Using @Autowired on the constructor tells Spring to inject the ProductRepository when creating ProductService.

3fill in blank

hard

Fix the error in the code by completing the annotation to inject the service.

Spring Boot

public class OrderController {
    @[1]
    private OrderService orderService;

    public void placeOrder() {
        orderService.processOrder();
    }
}

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

AComponent

BAutowired

CService

DRepository

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service or @Component instead of @Autowired for injection.

Forgetting to annotate the field and causing NullPointerException.

The @Autowired annotation is required to inject the OrderService dependency properly.

4fill in blank

hard

Fill both blanks to inject the repository and annotate the class as a Spring component.

Spring Boot

@[1]
public class CustomerRepository {

    @[2]
    private DataSource dataSource;

}

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AComponent

BAutowired

CRepository

DService

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component instead of @Repository for repository classes.

Forgetting @Autowired on the dataSource field.

The class should be annotated with @Repository to mark it as a Spring repository, and the dataSource field should be injected with @Autowired.

5fill in blank

hard

Fill all three blanks to create a service class with constructor injection and proper annotations.

Spring Boot

@[1]
public class PaymentService {

    private final PaymentRepository paymentRepository;

    @[2]
    public PaymentService([3] paymentRepository) {
        this.paymentRepository = paymentRepository;
    }
}

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

AService

BAutowired

CPaymentRepository

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component instead of @Service for service classes.

Forgetting @Autowired on the constructor.

Incorrect parameter type in the constructor.

The class is annotated with @Service, the constructor with @Autowired, and the parameter type is PaymentRepository for proper dependency injection.