Spring Boot Validation and Error Handling 3

Question 1

How do you implement cross-field validation (e.g., confirming a password matches) using Bean Validation?

Accepted Answer

Both A and B are valid approaches

Answer

Cross-field validation can be done with @ScriptAssert (quick, uses scripting engine) or a custom class-level constraint with a ConstraintValidator that receives the whole object; both are standard approaches.

Question 2

What is required to enable Bean Validation on Spring service-layer methods (not controllers)?

Accepted Answer

Annotate the service class with @Validated and ensure spring-boot-starter-validation is on the classpath

Answer

Placing @Validated on a Spring-managed bean (service) enables AOP-based method validation, causing constraint annotations on parameters and return values to be enforced automatically.

Question 3

What does cascaded validation (@Valid on a nested field) do in Bean Validation?

Accepted Answer

It triggers constraint validation recursively on the nested object's fields

Answer

Placing @Valid on a field or parameter instructs Bean Validation to recursively validate the constraints declared on the nested object's own fields and methods.

Question 4

When implementing @AssertTrue for custom field-level validation in a POJO, where should the annotated method be declared?

Accepted Answer

As a getter (isXxx / getXxx) inside the same class being validated

Answer

@AssertTrue is placed on a no-arg getter method within the POJO; the validator calls the method and expects it to return true, otherwise it reports a constraint violation.

Question 5

Which Spring Boot auto-configuration class is responsible for setting up the default error handling endpoint at /error?

Accepted Answer

ErrorMvcAutoConfiguration

Answer

ErrorMvcAutoConfiguration registers the BasicErrorController, DefaultErrorViewResolver, and supporting beans that power the default /error endpoint in Spring Boot.

Spring Boot Practice Test

Spring Boot Practice Test

Spring Boot Validation and Error Handling 3