Special character with Apache and Spring - spring

Question

I use the below code where I set credentials for basic https authentication to my server that uses Spring Security. Unfortunately I have problem with special characters like é,ò etc... I receive on server the question mark ? instead of correct character (both username and password). Someone know how to resolve it?
private RestClient(String username, String password) {
CredentialsProvider credsProvider = new BasicCredentialsProvider();
credsProvider.setCredentials(
new AuthScope(null, -1),
new UsernamePasswordCredentials(username, password));
HttpClient httpClient = HttpClients.custom().setDefaultCredentialsProvider(credsProvider).build();
setRequestFactory(new HttpComponentsClientHttpRequestFactory(httpClient));
}
public static synchronized RestClient getInstance(String username, String password){
if (instance == null){
instance = new RestClient(username, password);
instance.getMessageConverters().add(0, new StringHttpMessageConverter(Charset.forName("UTF-8")));
}
return instance;
}
and then I use for example
RestClient restClient = RestClient.getInstance(username, password);
if (queryParams!=null && queryParams.length!=0){
response = restClient.getForObject(addQueryParam(url, queryParams), Response.class);
}
I've tried even with URIEncoding="UTF-8" into server.xml of tomcat but the issue is still present.
UPDATE maybe I have fixed the issue setting the header manually:
private RestClient(String username, String password) {
String credential = Base64.getEncoder().encodeToString((username+":"+password).getBytes());
// create custom http headers for httpclient
List<BasicHeader> defaultHeaders = Arrays.asList(new BasicHeader(HttpHeaders.AUTHORIZATION, "Basic "+credential));
HttpClient httpClient = HttpClients.custom().setDefaultHeaders(defaultHeaders).build();
setRequestFactory(new HttpComponentsClientHttpRequestFactory(httpClient));
}
public static synchronized RestClient getInstance(String username, String password){
if (instance == null){
instance = new RestClient(username, password);
}
return instance;
}
I'm testing, let you know