NullPointerException while parsing XML callout response

Question

I am getting attempt to de-reference null object error the below callouts.

Class 1:

public class ProcessImgCallout {

    @future (callout=true)

    public static void SendImage(ID id) {
        system.debug('hello Mahesh '+id);

       String endPointURL = 'https://cloud.ocrsdk.com/processBusinessCard?exportformat=xml';
      String userName = '';// i removed username for security puropse
      String password = '';//i removed password for security puropse
      ContentVersion co = [Select id,pathOnClient,title,versionData  from ContentVersion where id =:id];
      Blob img =co.versionData;

        Blob headerValue = Blob.valueOf(userName + ':' + password);
         String authorizationHeader = 'BASIC ' +
           EncodingUtil.base64Encode(headerValue);
           Httprequest request = new HttpRequest();
             Http http = new Http();

             request.setMethod('POST');
              request.setEndpoint(endPointURL);
              request.setHeader('Authorization', authorizationHeader);
              request.setHeader('Content-Type', 'image/jpeg');
               request.setTimeout(2 * 60 * 1000);

               request.setBodyAsBlob(img);          

             HttpResponse res = http.send(request);  

              System.debug('responseBody: '+res.getBody());

         Dom.Document docx = new Dom.Document();
             //docx.load(responseUrl2);
             system.debug('@@@'+res.getbody());
             docx.load(res.getbody()); 
             //system.debug('$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ '+doc);
           String taskId = docx.getRootElement().getChildElement('task', null).getAttribute('id', null);
           system.debug(taskId);
        gettaskStatus.GetStatus(taskId);
    }
}

Class 2:

public class gettaskStatus {

    public static void GetStatus(String id){
        system.debug('hello mahesh i am with task id to get status'+id);
        //String taskid=id;


         String endPointURL = 'http://cloud.ocrsdk.com/getTaskStatus?taskId='+id;
        system.debug(endPointURL);
         String userName = '';//i removed username for security puropse
          String password = '';//i removed password for security puropse
          Blob headerValue = Blob.valueOf(userName + ':' + password);
         String authorizationHeader = 'BASIC ' +
           EncodingUtil.base64Encode(headerValue);
           Httprequest req = new HttpRequest();
             Http ht = new Http();

              req.setMethod('GET');
              req.setEndpoint(endPointURL);
              req.setHeader('Authorization', authorizationHeader);
              req.setTimeout(2 * 60 * 1000);
              //req.setHeader('Content-Type', 'image/jpeg');



             HttpResponse resp = ht.send(req);  

              System.debug('responseBody: to download url '+resp.getBody());

             Dom.Document doc = new Dom.Document();
             //docx.load(responseUrl2);
             system.debug('@@@'+resp.getbody());
             doc.load(resp.getbody()); 
             //system.debug('$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ '+doc);
           String resulturl = doc.getRootElement().getChildElement('task', null).getAttribute('resultUrl', null);
           system.debug(resulturl);
        GetLeadfromUrl.GetDownloadUrl(resulturl);

    }

}

Class 3:

public class GetLeadfromUrl {

     public static void GetDownloadUrl(String url){
         String ROOT_TAG = 'http://ocrsdk.com/schema/recognizedBusinessCard-1.0.xsd';
       // system.debug(url);
        String downloadurl=url;
         String newUrl=downloadurl.remove('amp;');
          system.debug(newUrl);

         String endPointURL =newUrl;

         Httprequest reqq = new HttpRequest();
             Http htt = new Http();

              reqq.setMethod('GET');
              reqq.setEndpoint(endPointURL);
              //reqq.setHeader('Authorization', authorizationHeader);
              //req.setHeader('Content-Type', 'image/jpeg');



             HttpResponse respp = htt.send(reqq);  

              System.debug('responseBody: to get final response '+respp.getBody());
                 Dom.Document doc = new Dom.Document();
             //d.load(responseUrl2);
             doc.load(respp.getbody());
             system.debug('@@@'+respp.getbody());
           Dom.XMLNode root = doc.getRootElement();
Dom.XMLNode businessCard = root.getChildElement('businessCard', 'http://ocrsdk.com/schema/recognizedBusinessCard-1.0.xsd');
Lead l = new Lead();

for (Dom.XmlNode node : businessCard.getChildren()) {
    if (node.getAttribute('type', null) != null) {
        if (node.getAttribute('type', null) == 'Phone') {
            if (node.getChildElement('value', ROOT_TAG) != null) {
                l.Phone = node.getChildElement('value', ROOT_TAG).getText();
            }
        }
        if (node.getAttribute('type', null) == 'Email') {
            if (node.getChildElement('value', ROOT_TAG) != null) {
                l.Email = node.getChildElement('value', ROOT_TAG).getText();
            }
        }
        if (node.getAttribute('type', null) == 'Company') {
            if (node.getChildElement('value', ROOT_TAG) != null) {
                l.Company = node.getChildElement('value', ROOT_TAG).getText();
            }
        }
        if (node.getAttribute('type', null) == 'Name') {
            if (node.getChildElement('value', ROOT_TAG) != null) {
                String name = node.getChildElement('value', ROOT_TAG).getText();
                String[] splited = name.split('\\s+');
                if(splited[0] != null || splited[0] != '')
                    l.FirstName = splited[0];

                if(splited[1] != null || splited[1] != '') 
                    l.LastName = splited[1];
            }
        }


    }
}

insert l;



    }  

}

Logs:

Class.GetLeadfromUrl.GetDownloadUrl: line 7, column 1
Class.gettaskStatus.GetStatus: line 37, column 1
Class.ProcessImgCallout.SendImage: line 39, column 1
16:10:36.29 (526284477)|FATAL_ERROR|System.NullPointerException: Attempt to de-reference a null object

Class.GetLeadfromUrl.GetDownloadUrl: line 7, column 1
Class.gettaskStatus.GetStatus: line 37, column 1
Class.ProcessImgCallout.SendImage: line 39, column 1
16:10:36.526 (526290597)|CUMULATIVE_LIMIT_USAGE
16:10:36.526 (526290597)|LIMIT_USAGE_FOR_NS|(default)|
Number of SOQL queries: 1 out of 200
Number of query rows: 1 out of 50000
Number of SOSL queries: 0 out of 20
Number of DML statements: 0 out of 150
Number of DML rows: 0 out of 10000
Maximum CPU time: 0 out of 60000
Maximum heap size: 0 out of 12000000
Number of callouts: 2 out of 100
Number of Email Invocations: 0 out of 10
Number of future calls: 0 out of 50
Number of queueable jobs added to the queue: 0 out of 1
Number of Mobile Apex push calls: 0 out of 10

16:10:36.526 (526290597)|CUMULATIVE_LIMIT_USAGE_END

16:10:36.29 (526366927)|CODE_UNIT_FINISHED|ProcessImgCallout.SendImage
16:10:36.29 (528606138)|EXECUTION_FINISHED

I am getting attempt to de-reference null object error in the second class. How can I fix it?

The actual response should be:

<?xml version="1.0" encoding="utf-8"?>
<response>
    <task id="5db7594c-721d-4ec4-b922-c07b03d24a76" registrationTime="2017-06-12T11:28:30Z" statusChangeTime="2017-06-12T11:28:30Z" status="Completed" filesCount="1" credits="0" resultUrl="https://ocrsdk.blob.core.windows.net/files/5db7594c-721d-4ec4-b922-c07b03d24a76.result?sv=2012-02-12&amp;se=2017-06-12T23%3A00%3A00Z&amp;sr=b&amp;si=downloadResults&amp;sig=MrRxA8o9g8T0X7GyFGvrOMdF%2FEmKr4wT8cqiPCQS6iw%3D" />
</response>

But I am getting the 1st callout response and 2nd callout response are both same , few times it is working fine and few time i am getting both callout has same response.

<?xml version="1.0" encoding="utf-8"?>
<response>
    <task id="5db7594c-721d-4ec4-b922-c07b03d24a76" registrationTime="2017-06-12T11:28:30Z" statusChangeTime="2017-06-12T11:28:30Z" status="Queued" filesCount="1" credits="0" estimatedProcessingTime="5" />
</response>

Answer 1

Your code assumes that responseUrl is specified:

public static void GetDownloadUrl(String url){
    // this value can be null            ^
    // so add a null check:
    if (String.isBlank(url)) return;

    // implementation
}