Java Map empty string value is omitted when sending response to postman

Question

My map is: Map<String, String>. The issue is empty values are not sended to the postman even though when I debbug are there.

This is the api:

@GetMapping(value = Routes.URI_SUFFIX_DATA_ZIPCODES_BY_CITY_AND_ZIPCODE, produces = {MediaType.APPLICATION_JSON_VALUE})
@RegisterMetricCallReceived(appService = "getStreetsByCityAndZipCode", version = "v1", type = TYPE_REST)
public Map<String,String> getStreetsByCityAndZipCode(HttpServletRequest request,
                                                               @RequestParam(name = "city") String city,
                                                               @RequestParam(name = "zipcode") String zipcode) {

        GetStreetByCityAndZipcode query = new GetStreetByCityAndZipcode();
        query.setCity(city);
        query.setZipcode(zipcode);
        Map<String, String> result = service.getStreets("eligibility", query).orElse(null);
        return result;
    }

When I debugg result object, it's like that:

"PLACE DU PRIEURE" -> "01043406"
"ROUTE DE BIERNE" -> ""
"ROUTE DE GENNES SUR GLAIZE" -> "01043405"
"RUE COURTE" -> "01043399"
"RUE D ANJOU" -> "01043398"
"RUE DE GENNES" -> "04311435"
"RUE DE L EGLISE" -> "01043397"
"RUE DE LA CHENAIE" -> "04106244"
"RUE DE LA POSTE" -> "01043400"
"RUE DES GRANDS JARDINS" -> "01043401"
"RUE DES JARDINS" -> ""
"RUE DES SPORTS" -> "04415887"

But from postman, I don't receive this two:

"ROUTE DE BIERNE" -> ""
"RUE DES JARDINS" -> ""

I receive just others which have not empty values:

"PLACE DU PRIEURE" -> "01043406"
"ROUTE DE GENNES SUR GLAIZE" -> "01043405"
"RUE COURTE" -> "01043399"
"RUE D ANJOU" -> "01043398"
"RUE DE GENNES" -> "04311435"
"RUE DE L EGLISE" -> "01043397"
"RUE DE LA CHENAIE" -> "04106244"
"RUE DE LA POSTE" -> "01043400"
"RUE DES GRANDS JARDINS" -> "01043401"
"RUE DES SPORTS" -> "04415887"

Answer 1

I found the issue, it was due to this Bean config, when I remove it, it works as fine:

 @Bean
 public JacksonFix jacksonFix(RequestMappingHandlerAdapter 
                                           annotationMethodHandlerAdapter) {
        return new JacksonFix(annotationMethodHandlerAdapter);
 }