Why DTOs matter in Spring Boot - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a simple DTO class with a private field and a getter.

Spring Boot

public class UserDTO {
    private String [1];

    public String getName() {
        return name;
    }
}

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

Aname

Bage

Cemail

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Using a field name that does not match the getter method.

Forgetting to make the field private.

The field name matches the getter getName(), which is typical in DTOs.

2fill in blank

medium

Complete the code to create a constructor for the DTO that sets the name field.

Spring Boot

public class UserDTO {
    private String name;

    public UserDTO([1]) {
        this.name = name;
    }
}

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

AString name

Bint age

Cboolean active

Ddouble salary

Attempts:

3 left

💡 Hint

Common Mistakes

Using a parameter type that does not match the field.

Using a different parameter name than the field.

The constructor parameter must match the field type and name to set the value correctly.

3fill in blank

hard

Fix the error in the DTO setter method to correctly set the field.

Spring Boot

public void setName(String name) {
    [1] = name;
}

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

AsetName

Bname

CUserDTO.name

Dthis.name

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the parameter to itself instead of the field.

Using the class name instead of this.

Using this.name refers to the field, avoiding confusion with the parameter name.

4fill in blank

hard

Fill both blanks to create a DTO from an entity object.

Spring Boot

public UserDTO([1] user) {
    this.name = user.[2]();
}

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

AUser

BgetName

CsetName

DUserDTO

Attempts:

3 left

💡 Hint

Common Mistakes

Using the DTO class as parameter type instead of the entity.

Calling a setter method instead of a getter on the entity.

The constructor takes a User entity and calls its getName() method to set the DTO's name.

5fill in blank

hard

Fill all three blanks to convert a list of entities to a list of DTOs using streams.

Spring Boot

List<UserDTO> dtos = users.stream()
    .map(user -> new UserDTO(user.[1]()))
    .[2](Collectors.[3]());

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

AgetName

Bcollect

CtoList

Dstream

Attempts:

3 left

💡 Hint

Common Mistakes

Using a setter method instead of a getter in the map.

Forgetting to collect the stream into a list.

Using incorrect collector methods.

The stream maps each user by calling getName(), then collects the results into a list using collect(Collectors.toList()).