title: HttpTransportSE.call method returns NullPointerException frequently
body: <p>I connect to a webservice to download master data for my app. So, in a single download the app will need to call the webservice a no of times with different indexes. </p>
  
  <p>During this, <em>HttpTransportSE.call</em> method returns <em>NullPointerException</em> for some indexes sometimes, otherwise it works fine.  </p>
  
  <p>My calling function is :</p>
  
  <pre><code>public String SoapAction(String[] values){
  
  String[] data = new String[] { "CompanyID", "Username", "Password", "indexNo", "DataString","lDate" };
  
      SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
  
  for(int i = 0; i &lt; data.length; i++){
    PropertyInfo property = new PropertyInfo();
    property.setName(data[i]);
    property.setNamespace(NAMESPACE);
    property.setType(PropertyInfo.STRING_CLASS);
    property.setValue(values[i]); 
  
    request.addProperty(property);
  }
  
  SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
  envelope.dotNet = true;
  envelope.implicitTypes = true;
  envelope.setOutputSoapObject(request);
  
  try{
    HttpTransportSE http = new HttpTransportSE(URL);
    http.debug = true;
    System.setProperty("http.keepAlive", "false");
  
    http.call(SOAP_ACTION, envelope);
  }catch (IOException e1) {
    e1.printStackTrace();         
    return "serverError";
  } catch (XmlPullParserException e1) {
    e1.printStackTrace();
    return "serverError";     
  } catch (Exception e) {
    e.printStackTrace();          
    return "serverError";
  }
  
  SoapPrimitive resultString = null;
  
  try{
    resultString = (SoapPrimitive)envelope.getResponse();
  }catch (SoapFault e) {
    e.printStackTrace();          
    return "serverError";
  }
  
  if(resultString != null){
    return resultString.toString();
  } else {
    return "serverError";
  }
  }
  </code></pre>
  
  <p>I did quite a bit of googling, but couldn't find a solution</p>
  
  <p>Here's the stacktrace:<br>
  02-06 14:01:14.136: W/System.err(1504): java.lang.NullPointerException</p>
  
  <p>02-06 14:01:14.136: W/System.err(1504):     at org.ksoap2.transport.ServiceConnectionSE.getResponseProperties(ServiceConnectionSE.java:85)</p>
  
  <p>02-06 14:01:14.136: W/System.err(1504):     at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:167)</p>
  
  <p>02-06 14:01:14.136: W/System.err(1504):     at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:96)</p>
  
  <p>02-06 14:29:50.026: W/System.err(1504):     at com.c2info.engine.WebServiceConnection.SoapAction(WebServiceConnection.java:49)</p>
  
  <p>02-06 14:29:50.026: W/System.err(1504):     at com.c2info.engine.DownloadData.downloadTasks(DownloadData.java:800)</p>
  
  <p>02-06 14:29:50.026: W/System.err(1504):     at com.c2info.engine.DownloadData$3.run(DownloadData.java:187)</p>