ResponseEntityExceptionHandler in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

How does ResponseEntityExceptionHandler handle exceptions?

Consider a Spring Boot controller that throws a MethodArgumentNotValidException. How does ResponseEntityExceptionHandler respond by default?

A It returns a 404 Not Found error without any body.

B It returns a 500 Internal Server Error with a generic message.

C It returns a 400 Bad Request with a detailed error body explaining validation failures.

D It ignores the exception and lets the request succeed.

💡 Hint

Think about what HTTP status code is appropriate for invalid input.

ResponseEntityExceptionHandler provides built-in handling for common exceptions like MethodArgumentNotValidException. It returns a 400 status with details about what validation failed.

📝 Syntax

intermediate

Correct override of handleHttpMessageNotReadable

Which method signature correctly overrides handleHttpMessageNotReadable in a class extending ResponseEntityExceptionHandler?

A public ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request)

B protected ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request)

C protected ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatus status, WebRequest request)

D protected ResponseEntity<Object> handleHttpMessageNotReadable(Exception ex, HttpHeaders headers, HttpStatusCode status, WebRequest request)

💡 Hint

Check the exact parameter types and access modifier in the superclass method.

The method to override uses protected access and HttpStatusCode for the status parameter in Spring Boot 3+. The exception type must be HttpMessageNotReadableException.

🔧 Debug

advanced

Why does custom exception handler not get called?

You created a class extending ResponseEntityExceptionHandler and annotated it with @ControllerAdvice. But your custom handleMethodArgumentNotValid method is never called. What is the most likely cause?

A The method signature does not exactly match the superclass method signature.

B The exception is not thrown by any controller method.

C You forgot to add <code>@ExceptionHandler</code> annotation on the method.

D The class is missing <code>@RestControllerAdvice</code> annotation instead of <code>@ControllerAdvice</code>.

💡 Hint

Check method signatures carefully when overriding methods.

Overriding methods must match the exact signature of the superclass method. If the signature differs, the method will not override and will not be called.

❓ state_output

advanced

What is the HTTP status code returned by default for UnsupportedMediaTypeException?

When a controller receives a request with an unsupported media type, and ResponseEntityExceptionHandler handles HttpMediaTypeNotSupportedException, what HTTP status code is returned by default?

A 406 Not Acceptable

B 400 Bad Request

C 500 Internal Server Error

D 415 Unsupported Media Type

💡 Hint

Think about the meaning of the status codes related to media types.

The HttpMediaTypeNotSupportedException is handled by returning 415 status code, which means the media type is not supported by the server.

🧠 Conceptual

expert

Why extend ResponseEntityExceptionHandler instead of using @ExceptionHandler alone?

In Spring Boot, what is the main advantage of extending ResponseEntityExceptionHandler in your @ControllerAdvice class compared to only defining @ExceptionHandler methods?

A It provides default handling for many common Spring MVC exceptions, reducing boilerplate code.

B It forces all exceptions to return HTTP 200 status.

C It disables the default Spring Boot error page and replaces it with a blank response.

D It automatically logs all exceptions without extra code.

💡 Hint

Think about what ResponseEntityExceptionHandler already implements for you.

Extending ResponseEntityExceptionHandler gives you ready-made handlers for many exceptions like validation errors, media type errors, etc. This saves you from writing repetitive code.