UserDetailsService implementation in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the UserDetailsService implementation class.

Spring Boot

public class [1] implements UserDetailsService {
    // implementation
}

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

AUserDetails

BUserService

CMyUserDetailsService

DUserRepository

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name that does not reflect its purpose.

Not implementing UserDetailsService interface.

The class implementing UserDetailsService should have a clear name like MyUserDetailsService.

2fill in blank

medium

Complete the method signature to override loadUserByUsername.

Spring Boot

@Override
public [1] loadUserByUsername(String username) throws UsernameNotFoundException {
    // method body
}

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Avoid

BUserDetails

CUser

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Returning void or wrong type.

Missing the @Override annotation.

The method loadUserByUsername must return a UserDetails object.

3fill in blank

hard

Fix the error in fetching user by username from repository.

Spring Boot

User user = userRepository.[1](username);
if (user == null) {
    throw new UsernameNotFoundException("User not found");
}

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AfindByUsername

BfindById

CgetUser

DloadUser

Attempts:

3 left

💡 Hint

Common Mistakes

Using findById which expects an ID, not username.

Using non-existent methods like getUser or loadUser.

The repository method to find user by username is usually named findByUsername.

4fill in blank

hard

Fill both blanks to return a UserDetails object with username and password.

Spring Boot

return new org.springframework.security.core.userdetails.User([1], [2], new ArrayList<>());

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Auser.getUsername()

Buser.getPassword()

Cuser.getEmail()

Duser.getRoles()

Attempts:

3 left

💡 Hint

Common Mistakes

Using email instead of username.

Using roles where password is expected.

The UserDetails constructor needs username and password from the user object.

5fill in blank

hard

Fill all three blanks to complete the UserDetailsService implementation with repository injection and method.

Spring Boot

public class MyUserDetailsService implements UserDetailsService {

    private final [1] userRepository;

    public MyUserDetailsService([2] userRepository) {
        this.userRepository = userRepository;
    }

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.[3](username);
        if (user == null) {
            throw new UsernameNotFoundException("User not found");
        }
        return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());
    }
}

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

AUserRepository

CfindByUsername

DUserService

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong repository type or service class.

Using incorrect method names for fetching user.

The repository is injected via constructor and used to find user by username.