How to Handle Exception Responses with Spring Boot Rest When Using @ControllerAdvice

How can I configure Spring Boot Rest to prevent empty response bodies for exceptions not managed by @ControllerAdvice?

When developing RESTful APIs with Spring Boot, it's common to use @ControllerAdvice to centralize exception handling. However, there may be cases where exceptions throw an empty response body, particularly for those not explicitly caught by the defined advices in your application. This article explores how to properly handle exceptions to avoid empty response bodies and ensure a consistent and informative response structure.

@ControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(Exception.class)
    public ResponseEntity<Object> handleAllExceptions(Exception ex) {
        // Create a meaningful error response
        Map<String, Object> errorDetails = new HashMap<>();
        errorDetails.put("message", ex.getMessage());
        errorDetails.put("timestamp", LocalDateTime.now());
        return new ResponseEntity<>(errorDetails, HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

Causes

• The exception is not being caught by any defined @ExceptionHandler method in @ControllerAdvice.
• Default behavior of Spring's exception handling may result in empty responses for unhandled exceptions.

Solutions

• Ensure that you have a global exception handler defined in your @ControllerAdvice class, capturing all necessary exceptions.
• Implement a default handler or use a generic Exception class to handle unexpected exceptions, providing a standardized response.
• Modify the response body by using the ResponseEntity class to include meaningful error messages and appropriate HTTP status codes.

Mistake: Only handling specific exceptions without a fallback catch-all method.

Solution: Always include a general Exception handler to catch any unanticipated errors.

Mistake: Returning void or null in response methods for errors.

Solution: Always return a structured ResponseEntity object with a message and status.