Validation error responses in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add validation to the 'name' field using annotations.

Spring Boot

@NotBlank(message = "Name is required")
private String [1];

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Ausername

Bvalue

Cname

Dfield

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong variable name in the annotation.

Forgetting to add the annotation above the field.

The field to validate is named 'name', so the annotation applies to 'name'.

2fill in blank

medium

Complete the code to handle validation errors by returning a bad request response.

Spring Boot

@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<String> handleValidationException([1] ex) {
    return ResponseEntity.badRequest().body("Validation failed");
}

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AValidationException

BMethodArgumentNotValidException

CException

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic Exception instead of the specific validation exception.

Mismatching the exception type in the method parameter.

The exception handler must catch MethodArgumentNotValidException to handle validation errors.

3fill in blank

hard

Fix the error in extracting the first validation error message from the exception.

Spring Boot

String errorMessage = ex.getBindingResult().getFieldErrors().get([1]).getDefaultMessage();

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Aex

B1

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 1 which causes IndexOutOfBoundsException if only one error exists.

Using -1 which is invalid for list indexing.

The first error is at index 0 in the list of field errors.

4fill in blank

hard

Fill both blanks to create a map of field names to error messages from validation errors.

Spring Boot

Map<String, String> errors = ex.getBindingResult().getFieldErrors().stream()
    .collect(Collectors.[1](error -> error.getField(), error -> error.[2]()));

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AtoMap

BgetDefaultMessage

CgetMessage

DtoList

Attempts:

3 left

💡 Hint

Common Mistakes

Using toList instead of toMap causes wrong collection type.

Using getMessage instead of getDefaultMessage returns less useful info.

toMap collects entries into a map; getDefaultMessage gets the error message string.

5fill in blank

hard

Fill all three blanks to return a ResponseEntity with the error map and HTTP status BAD_REQUEST.

Spring Boot

return new ResponseEntity<>([1], [2].[3]);

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Aerrors

BHttpStatus

CBAD_REQUEST

DResponseEntity

Attempts:

3 left

💡 Hint

Common Mistakes

Using ResponseEntity instead of HttpStatus for the status argument.

Passing wrong variable as body.

The body is 'errors', status is HttpStatus.BAD_REQUEST for validation failure.