Business logic in services in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Spring Boot

@[1]
public class UserService {
    // business logic here
}

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

AService

BComponent

CRepository

DController

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Controller instead of @Service

Forgetting to add any annotation

Using @Repository which is for data access

The @Service annotation marks the class as a service component in Spring Boot, which holds business logic.

2fill in blank

medium

Complete the code to inject a repository into the service using Spring Boot.

Spring Boot

@Service
public class OrderService {
    private final OrderRepository orderRepository;

    public OrderService([1] orderRepository) {
        this.orderRepository = orderRepository;
    }
}

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Afinal

BOrderRepository

C@Autowired

Dprivate

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Autowired as a parameter type

Using 'final' or 'private' as parameter type

Forgetting to specify the repository type

The constructor parameter must be of type OrderRepository to inject the repository instance.

3fill in blank

hard

Fix the error in the method that saves an order in the service.

Spring Boot

public void saveOrder(Order order) {
    orderRepository.[1](order);
}

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Asave

BsaveOrder

Cinsert

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent method like saveOrder

Using insert which is not in JpaRepository

Using add which is not a repository method

The correct method to save an entity in Spring Data JPA repository is save.

4fill in blank

hard

Fill both blanks to create a method that finds an order by ID and returns it or null if not found.

Spring Boot

public Order getOrderById(Long id) {
    return orderRepository.[1](id).[2](null);
}

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AfindById

BorElse

Cget

DorElseGet

Attempts:

3 left

💡 Hint

Common Mistakes

Using get() without checking if present

Using orElseGet with null directly

Using non-existent repository methods

findById returns an Optional. Using orElse(null) returns the order or null if not found.

5fill in blank

hard

Fill all three blanks to create a method that updates an order's status if it exists.

Spring Boot

public boolean updateOrderStatus(Long id, String status) {
    return orderRepository.findById([1]).map(order -> {
        order.setStatus([2]);
        orderRepository.[3](order);
        return true;
    }).orElse(false);
}

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

Aid

Bstatus

Csave

Dorder

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names for parameters

Forgetting to save the updated order

Returning true without updating

The method finds the order by id, sets the new status, saves the order with save, and returns true if successful.