Updating work item using Rest API (HttpPut) is not working!

Hi,

 I am working on updating a workitem status / description using Rest APIs(HttpPut). I am following the steps detailed in the OSLC Workshop book. Below is the code snippet. But some how work item is not getting updated after executing the code.

I am using JTS 4.0.1.

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private void updateChangeRequest(String usrName, String password, String paName, String wiID, String status, String description)
 {
  String server = "https://localhost:9443/ccm";
  HttpResponse response = null;
  String catalogURI;
  String jsonObj="";
  try {
     catalogURI = getServiceProviderCatalog(usrName,password);
    
    HttpClient httpclient = new DefaultHttpClient();
    HttpUtils.setupLazySSLSupport(httpclient);
    
    String projectAreaURI = getServiceProvider(usrName,password,catalogURI, paName);
    String simpleQueryURI = getSimpleQueryURI(usrName,password,projectAreaURI);
   
     ChangeRequest cr = getChangeRequest(usrName, password,simpleQueryURI, wiID);
    cr.setDcDescription(description); //updating the description only
    
    HttpResponse response1 = updateChangeRequest(cr,server,usrName,password,httpclient);
    
    HttpUtils.printResponseHeaders(response1);
    HttpUtils.printResponseBody(response1);
    
   } catch (ClientProtocolException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   } catch (XPathExpressionException e) {
    e.printStackTrace();
   } catch (InvalidCredentialsException e) {
    e.printStackTrace();
   } finally {
    // Shutdown the HTTP connection
   
   }

 
 }
 

private HttpResponse updateChangeRequest(final ChangeRequest cr, String server,String login, String password, HttpClient httpclient) throws InvalidCredentialsException, IOException {
  // How to fill the request body (Content Producer)
  ContentProducer cp = new ContentProducer() {
      public void writeTo(OutputStream outstream) throws IOException {
          Writer writer = new OutputStreamWriter(outstream, HTTP.UTF_8);       
          cr.writeXML(writer);
          writer.flush();
      }
  };

  HttpEntity entity = new EntityTemplate(cp);
  HttpPut put = new HttpPut(cr.getUri());  
  put.addHeader("Accept", "application/rdf+xml");
  put.addHeader("Content-type", "application/xml");
  put.setEntity(entity);
  
  // Call the PUT method against the Change Request URI
  return HttpUtils.sendPutForSecureDocument(
       server, cp, put, login, password, httpclient);
 }

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Anyone has faced similar challenges & was able to resolve it, please let me know.

Thanks
Guru