What are the best practices for designing a custom exception handling framework in Spring Boot?

A well-designed custom exception handling framework in Spring Boot centralizes error translation using @ControllerAdvice and a small hierarchy of domain-specific exceptions, so every controller returns consistent, meaningful error responses.

Key Points: • Define a base custom exception, such as ApplicationException, and extend it for specific cases like ResourceNotFoundException or ValidationException. • Use a single @ControllerAdvice class with @ExceptionHandler methods mapped to each exception type and the correct HTTP status. • Return a standardized error response body containing a message, error code, timestamp, and optionally field-level validation details. • Avoid leaking internal stack traces or implementation details in production error responses. • Log exceptions at the point of handling so error visibility doesn't depend on the caller.

Example: When a service throws ResourceNotFoundException, the global handler catches it once and returns a 404 with a consistent JSON body, instead of every controller needing its own try-catch block.

Code Example:

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<ErrorResponse> handleNotFound(ResourceNotFoundException ex) {
        ErrorResponse body = new ErrorResponse("NOT_FOUND", ex.getMessage());
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(body);
    }
}

Interview Tip: A concise interview answer is:

"I design a small hierarchy of custom exceptions extending a base ApplicationException, then handle them all in one @ControllerAdvice with @ExceptionHandler methods that map each type to the right HTTP status and a consistent error response body. That keeps error handling centralized instead of scattered across controllers."