我正在使用Selenium和测试ng来验证url是返回200（成功）还是失败（501）错误

Question

我正在使用Selenium和测试ng来验证url是否返回200（成功）或失败（501）错误。但是我得到空指针异常。请帮我解决这个问题。

以下是代码

public void Test_Demo_Services() throws Exception {

              System.out.println("Entering Login test method");

          //Logging in
              this.oService = new WebService(this.oUrl.getSMHeartBeatUrl());
              Boolean     bbb=this.oService.checkWebService(this.oUrl.getSMHeartBeatUrl());


              System.out.println("Exiting Login test method");
       }

Webservices.java

public boolean checkWebService(String sUrl) throws Exception {      


       // Create Gson object (serialize and deserialize json strings)
       Gson gson = new GsonBuilder().create();

              UrlBuilder oUrl = new UrlBuilder(sUrl);  //Base URL..no port     or anything needed

              //String sServiceUrl = oUrl.getWFMSVCActivitiesUrl();

              String sServiceUrl = oUrl.getSMHeartBeatUrl();

              //Create your http client
              CloseableHttpClient httpclient =     HttpClientBuilder.create().build();

              //Create http get object
              HttpGet getRequest = new HttpGet(sServiceUrl); 

              //getRequest.addHeader("WMT-UserId",this.getUserID());
              getRequest.addHeader("WMT-Security-ID", this.sAuthToken[0]);
              getRequest.addHeader("WMT-Token", this.sAuthToken[1]);

              //submit request and save response
              HttpResponse response = httpclient.execute(getRequest);

              //get status code from response
              int sStatusCode = response.getStatusLine().getStatusCode();

              if(sStatusCode == 200 || sStatusCode == 201) {
              ReportResults("PASS", "getActivitiesAll webservice executed     successfully", false);

              return true;

              }
              else{
                     ReportResults("FAIL", "getActivitiesAll webservice     unsuccessful due to: " + this.getErrorMessage() , false);
                         this.setErrorMessage(response.getStatusLine().toString());
                     return false;

              }