Validation error response formatting in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to annotate a field for validation.

Spring Boot

public class User {
    @[1](message = "Name cannot be empty")
    private String name;
}

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ANotNull

BMax

CMin

DSize

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Size without specifying min and max

Using @Min or @Max on a String field

The @NotNull annotation ensures the field is not null, which is a basic validation for required fields.

2fill in blank

medium

Complete the code to handle validation errors in a controller advice.

Spring Boot

@RestControllerAdvice
public class ValidationExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Map<String, String>> handleValidationExceptions(
            [1] ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getFieldErrors().forEach(error ->
                errors.put(error.getField(), error.getDefaultMessage()));
        return ResponseEntity.badRequest().body(errors);
    }
}

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AMethodArgumentNotValidException

BConstraintViolationException

CIllegalArgumentException

DValidationException

Attempts:

3 left

💡 Hint

Common Mistakes

Using ConstraintViolationException which is for different validation context

Using generic exceptions like IllegalArgumentException

The MethodArgumentNotValidException is thrown when validation on an argument annotated with @Valid fails.

3fill in blank

hard

Fix the error in the code to extract field errors correctly.

Spring Boot

ex.getBindingResult().get[1]().forEach(error ->
    errors.put(error.getField(), error.getDefaultMessage()));

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AFieldErrorsList

BFieldError

CFieldErrors

DFieldErrorsCollection

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names like getFieldError or getFieldErrorsList

Using singular form instead of plural

The correct method is getFieldErrors() which returns a list of field errors.

4fill in blank

hard

Fill both blanks to create a custom error response class with fields for message and timestamp.

Spring Boot

public class ErrorResponse {
    private String [1];
    private LocalDateTime [2];

    public ErrorResponse(String message, LocalDateTime timestamp) {
        this.message = message;
        this.timestamp = timestamp;
    }

    // getters and setters
}

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Amessage

Berror

Ctimestamp

Dtime

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent field names that don't match constructor

Using generic names like 'error' or 'time' instead of 'message' and 'timestamp'

The fields should be named message and timestamp to match the constructor and common naming conventions.

5fill in blank

hard

Fill all three blanks to build a method that returns a formatted error response with HTTP status and body.

Spring Boot

public ResponseEntity<ErrorResponse> buildErrorResponse(String [1], HttpStatus [2]) {
    ErrorResponse errorResponse = new ErrorResponse([1], LocalDateTime.now());
    return ResponseEntity.status([2]).body(errorResponse);
}

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Amessage

Bstatus

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names that don't match method signature

Confusing the order of parameters

The method uses message as the error text parameter and status as the HTTP status. These are used to create the response entity.