Getting 400 (bad request) when trying to update Work Item on VSO with REST API from Java client

Question

I'm trying to change (update) Visual Studio Online work item (of type User Story) using REST API (https://www.visualstudio.com/en-us/docs/integrate/api/wit/work-items#update-work-items)

private static String addCommenttoStackOverflow() throws IOException {
    String url = "https://<myproject>.visualstudio.com/DefaultCollection/_apis/wit/workitems/<specific id>?api-versoin=1.0";
    HttpUriRequest request = RequestBuilder.patch(url)
            .setHeader(HttpHeaders.CONTENT_TYPE, "application/json-patch+json")
            .setHeader("Authorization", "Basic " + getVsoAuthenticationString())
            .setEntity(EntityBuilder.create()
                    .setContentEncoding("UTF8")
                    .setText("[{\"op\":\"add\",\"path\":\"/fields/System.History\",\"value\":\"JavaScript implementation for Microsoft Account\"}]")
                    .build())
            .build();


    try(CloseableHttpClient httpclient = HttpClients.createDefault()) {
        try(CloseableHttpResponse response = httpclient.execute(request)) {

            System.out.println("Status = " + response.getStatusLine());
            HttpEntity entity =response.getEntity();
            System.out.println(entity.toString());
            System.out.println(entity.getContent().toString());
            ResponseHandler<String> handler = new BasicResponseHandler();
            return handler.handleResponse(response);
        }
    }
}

I'm using Apache HttpComponents for Java REST client and basic basic authentication (PAT). I'd successfully used very similar code for querying, but unable to update.

Answer 1

Refer to this code below:

byte[] encodedBytes = Base64.getEncoder().encode("test:{your personal access token}".getBytes());
            String basedToken=new String(encodedBytes);
            HttpClient httpClient = HttpClientBuilder.create().build();

            HttpPatch patchRequest=new HttpPatch("https://{account}.visualstudio.com/DefaultCollection/_apis/wit/workitems/{work item id}?api-version=1.0");
            StringEntity input = new StringEntity("[{\"op\":\"add\",\"path\":\"/fields/System.History\",\"value\":\"JavaScript implementation for Microsoft Account2\"}]");
            input.setContentType("application/json-patch+json");
            patchRequest.setEntity(input);
            patchRequest.setHeader("Authorization", "Basic "+basedToken);

            HttpResponse response = httpClient.execute(patchRequest);



            BufferedReader br = new BufferedReader(
                            new InputStreamReader((response.getEntity().getContent())));

            String output;
            System.out.println("Output from Server .... \n");
            while ((output = br.readLine()) != null) {
                System.out.println(output);
            }