HttpHeaders headers = new HttpHeaders();
        headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
        httpEntity = new HttpEntity<String>(headers);

    public List<OfferedServiceTO> getOfferedServices() {
// Fails with the unrecognized field "service" exception, using the XML document

//      return restTemplate.getForObject(
//              dataServiceUriTemplate,
//              OfferedServiceTOList.class,
//              OFFERED_SERVICES
//          );
//      // public class OfferedServiceTOList extends ArrayList<OfferedServiceTO> {}

        // Debugging:
        ResponseEntity<String> resp = restTemplate.exchange(
                dataServiceUriTemplate,
                HttpMethod.GET, httpEntity,
                String.class,
                OFFERED_SERVICES
            );
        String str = resp.getBody();

        // If Json, fails with "Problem: abstract types can only be instantiated with additional type information" exception
        ResponseEntity<Source> response = restTemplate.exchange(
                dataServiceUriTemplate,
                HttpMethod.GET, httpEntity,
                Source.class,
                OFFERED_SERVICES
            );

        List<OfferedServiceTO> result = (OfferedServiceTOList) marshaller.unmarshal(response.getBody());
        return result;
    }