Implementing Error Handling

{
  "type": "https://api.shop.com/errors/insufficient-funds",
  "title": "Insufficient funds",
  "status": 402,
  "detail": "Account balance is below required amount",
  "instance": "/payments/pay_123",
  "code": "INSUFFICIENT_FUNDS",
  "balance": 12.50,
  "required": 49.95
}

@RestControllerAdvice
class GlobalErrors {
  @ExceptionHandler(EntityNotFoundException.class)
  ProblemDetail notFound(EntityNotFoundException ex) {
    var p = ProblemDetail.forStatusAndDetail(HttpStatus.NOT_FOUND, ex.getMessage());
    p.setProperty("code", "NOT_FOUND");
    return p;
  }
  @ExceptionHandler(MethodArgumentNotValidException.class)
  ProblemDetail validation(MethodArgumentNotValidException ex) {
    var p = ProblemDetail.forStatus(HttpStatus.BAD_REQUEST);
    p.setProperty("errors", ex.getFieldErrors().stream()
        .map(f -> Map.of("field", f.getField(), "code", f.getCode())).toList());
    return p;
  }
}