@Valid annotation on request body in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @Valid annotation in Spring Boot?

The <code>@Valid</code> annotation is used to tell Spring Boot to check the data in the request body against the validation rules defined in the model class before processing it.

beginner

Where do you place the @Valid annotation in a Spring Boot controller method?

You place @Valid right before the request body parameter in the controller method, for example: public ResponseEntity method(@Valid @RequestBody MyModel model).

intermediate

What happens if the request body fails validation when using @Valid?

Spring Boot automatically returns a 400 Bad Request response with details about which validation rules failed, preventing the controller method from running.

intermediate

Which Java package provides the validation annotations used with @Valid?

The validation annotations like @NotNull, @Size, and @Email come from the jakarta.validation.constraints package.

intermediate

How can you customize the error messages shown when validation fails with @Valid?

You can add a message attribute to each validation annotation, for example: @NotNull(message = "Name is required") to show a friendly message.

What does the @Valid annotation do in a Spring Boot controller?

A Logs the request body content

B Converts the request body to JSON

C Encrypts the request body data

D Validates the request body data against model rules

@Valid triggers validation of the request body data before the controller processes it.

Where should @Valid be placed in a controller method?

A Before the method name

B Before the request body parameter

C After the return type

D On the class declaration

@Valid goes right before the parameter annotated with @RequestBody.

Which HTTP status code does Spring Boot return if validation fails with @Valid?

A 400 Bad Request

B 500 Internal Server Error

C 404 Not Found

D 200 OK

Validation failure results in a 400 Bad Request response.

Which package provides annotations like @NotNull used with @Valid?

A org.springframework.web.bind.annotation

B java.util

C jakarta.validation.constraints

D java.lang

Validation annotations come from jakarta.validation.constraints.

How can you provide a custom error message for a validation rule?

A By setting <code>message</code> attribute in the validation annotation

B By overriding the controller method

C By changing the HTTP status code

D By adding <code>@CustomMessage</code> annotation

Custom messages are set using the message attribute inside validation annotations.

Explain how the @Valid annotation works on a request body in Spring Boot and what happens when validation fails.

Think about how Spring Boot checks data before running your code.

Describe how to customize validation error messages when using @Valid in Spring Boot.

Focus on how to make validation feedback clearer.