findUserById.java

     public FindUserResponse findUserById() 
     {
        String username = "chathuranga";
        String password = "123";
        Integer userId = 1;

        String url = "http://localhost:" + port + "/users/" + userId;

        String authorizationHeader = "Basic " + DatatypeConverter.printBase64Binary((username + ":" + password).getBytes());

        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.setContentType(MediaType.APPLICATION_JSON);
        requestHeaders.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
        requestHeaders.add("Authorization", authorizationHeader);

        //fields are empty
        AddUserRequest addUserRequest = new AddUserRequest();

        HttpEntity<AddUserRequest> requestEntity = new HttpEntity<>(addUserRequest, requestHeaders);

        ResponseEntity<FindUserResponse> responseEntity = testRestTemplate.exchange(
                url,
                HttpMethod.GET,
                requestEntity,
                FindUserResponse.class
        );

        FindUserResponse findUserResponse = responseEntity.getBody();
        return findUserResponse;
    }