Handling not found exceptions in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of handling 'not found' exceptions in Spring Boot?

To provide a clear and user-friendly response when a requested resource does not exist, avoiding server errors and improving user experience.

beginner

Which annotation is commonly used in Spring Boot to handle exceptions globally?

The @ControllerAdvice annotation is used to define a class that handles exceptions across all controllers globally.

intermediate

How do you return a 404 status code when a resource is not found in Spring Boot?

Throw a custom exception (e.g., ResourceNotFoundException) and handle it with @ExceptionHandler to return ResponseEntity with HttpStatus.NOT_FOUND (404).

intermediate

What is the role of @ExceptionHandler in Spring Boot?

It marks a method that handles specific exceptions thrown in controller methods, allowing custom responses for errors like 'not found'.

intermediate

Why is it better to use custom exceptions for 'not found' cases instead of returning null?

Custom exceptions clearly indicate an error state, making the code easier to read and maintain, and allowing centralized error handling with proper HTTP responses.

Which HTTP status code should you return when a resource is not found?

A 500

B 404

C 200

D 302

404 means 'Not Found', which is the correct status when a requested resource does not exist.

Which Spring Boot annotation allows you to handle exceptions globally?

A @ControllerAdvice

B @RestController

C @Service

D @Repository

@ControllerAdvice lets you define global exception handling logic.

What does the @ExceptionHandler annotation do?

A Handles specific exceptions in controller methods

B Defines a REST endpoint

C Injects dependencies

D Marks a service class

@ExceptionHandler marks methods that handle exceptions thrown in controllers.

What is a good practice when a resource is not found?

A Return null silently

B Return 200 with empty body

C Throw a custom exception and return 404

D Throw a generic exception

Throwing a custom exception and returning 404 clearly communicates the error.

Where do you typically define exception handling methods in Spring Boot?

A In the application.properties file

B Inside the main application class

C In the entity classes

D In a class annotated with @ControllerAdvice

Exception handling methods are usually placed in a @ControllerAdvice class for global handling.

Explain how to handle a 'not found' exception in Spring Boot to return a 404 status code.

Think about how to signal missing data clearly to the user.

Describe why using custom exceptions for 'not found' cases improves your Spring Boot application.

Consider maintainability and user experience.