DTO validation in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a validation annotation that ensures the 'name' field is not empty.

Spring Boot

public class UserDTO {
    @[1]
    private String name;

    // getters and setters
}

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

ASize

BNotEmpty

CEmail

DMin

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Size without specifying min value

Using @Email for a name field

Using @Min which is for numbers

The @NotEmpty annotation ensures the 'name' field is not null or empty.

2fill in blank

medium

Complete the code to validate that the 'email' field contains a valid email format.

Spring Boot

public class UserDTO {
    @[1]
    private String email;

    // getters and setters
}

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

ANotNull

BPattern

CEmail

DNotBlank

Attempts:

3 left

💡 Hint

Common Mistakes

Using @NotNull which only checks for null, not format

Using @Pattern without regex

Using @NotBlank which only checks for empty strings

The @Email annotation checks that the string is a valid email format.

3fill in blank

hard

Fix the error in the code by adding the correct annotation to ensure 'age' is at least 18.

Spring Boot

public class UserDTO {
    @[1]
    private int age;

    // getters and setters
}

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

AMax(18)

BPositive

CSize(min=18)

DMin(18)

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Max instead of @Min

Using @Size which is for strings or collections

Using @Positive which only checks greater than zero

The @Min(18) annotation ensures the 'age' field value is at least 18.

4fill in blank

hard

Fill both blanks to create a DTO field 'password' that must be at least 8 characters and not blank.

Spring Boot

public class UserDTO {
    @[1]
    @[2](min = 8)
    private String password;

    // getters and setters
}

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

ANotBlank

BNotNull

CSize

DPattern

Attempts:

3 left

💡 Hint

Common Mistakes

Using @NotNull instead of @NotBlank

Using @Pattern without regex

Using @Size without min parameter

@NotBlank ensures the password is not empty or just spaces.
@Size(min = 8) ensures the password has at least 8 characters.

5fill in blank

hard

Fill all three blanks to create a DTO field 'username' that is not null, has length between 5 and 15, and matches only letters and digits.

Spring Boot

public class UserDTO {
    @[1]
    @[2](min = 5, max = 15)
    @[3](regexp = "^[a-zA-Z0-9]+$")
    private String username;

    // getters and setters
}

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

ANotNull

BSize

CPattern

DNotBlank

Attempts:

3 left

💡 Hint

Common Mistakes

Using @NotBlank instead of @NotNull

Omitting max in @Size

Using wrong regex in @Pattern

@NotNull ensures the username is not null.
@Size(min = 5, max = 15) restricts length.
@Pattern restricts characters to letters and digits.