RestTemplate POST - handle response

Question

I am aware of the similar posts and i checked them, but non of them could help me.

I want to POST to a API (that manages for examples tasks) that requires three parameters and a basic auth. In postman it works. I provide the body like:

{
    "title": "foo",
    "description": "bar",
    "completed": "false"
}

and set the basic auth (with username and password). The API sends a response like this:

{
  "id": 0001
}

Everything works fine if i send a POST to the api, but now i want to implement it in java. I am getting a 400 bad request if i try to send a POST: HttpClientErrorException: 400 Bad Request (DefaultResponseErrorHandler). The Task and TaskResponse are pojo's with the fields like in the request and response and a no-arg/full-arg constructor, getter and setter.

 Task task = new Task("foo", "bar", false);
        RestTemplate template = new RestTemplate();
        HttpEntity<Task> httpEntity = new HttpEntity<>(task, createHttpHeader());
        ResponseEntity<TaskResponse> result = template.exchange(uri, HttpMethod.POST, httpEntity, TaskResponse.class);

private HttpHeaders createHttpHeader() {
        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.setContentType(MediaType.APPLICATION_JSON);
        requestHeaders.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
        requestHeaders.set("Authorization", createBasicAuthHeaderValue(username, password));
        return requestHeaders;
    }

    private String createBasicAuthHeaderValue(String username, String password) {
        String credentials = username + ":" + password;
        byte[] base64Credentials = Base64.encodeBase64(credentials.getBytes());
        return "Basic " + Arrays.toString(base64Credentials);
    }

Answer 1

I discovered, that this implementation is fine. It accepts String as a Response type. There was another problem, but not related to this context.