Service calling repository in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to inject the repository into the service class.

Spring Boot

public class UserService {
    private final UserRepository [1];

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
}

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

AuserRepo

BuserRepository

Crepository

Drepo

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name than the constructor parameter

Forgetting to declare the field

The service class should declare a field named userRepository to match the constructor parameter and follow common naming conventions.

2fill in blank

medium

Complete the code to annotate the service class for Spring to detect it as a service.

Spring Boot

[1]
public class UserService {
    // service methods
}

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A@Repository

B@Component

C@Controller

D@Service

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Repository instead of @Service

Forgetting to annotate the class

The @Service annotation marks the class as a service component in Spring.

3fill in blank

hard

Fix the error in the service method to call the repository's findById method correctly.

Spring Boot

public User getUserById(Long id) {
    return userRepository.[1](id).orElse(null);
}

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AgetOne

BgetById

CfindById

DfindOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using deprecated methods like getOne

Using methods that do not return Optional

The correct repository method to find by ID returning Optional is findById.

4fill in blank

hard

Fill both blanks to complete the service method that saves a user using the repository.

Spring Boot

public User saveUser(User [1]) {
    return userRepository.[2]([1]);
}

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Auser

Bsave

Cadd

Dentity

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect parameter names

Using wrong repository method names like add

The method parameter should be named user and the repository method to save is save.

5fill in blank

hard

Fill all three blanks to complete the service method that deletes a user by ID using the repository.

Spring Boot

public void deleteUserById([1] [2]) {
    userRepository.[3]([2]);
}

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ALong

Bid

CdeleteById

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter types

Using wrong method names like delete

The method parameter type is Long, the parameter name is id, and the repository method to delete by ID is deleteById.