I am trying to connect to a weather API.

The class was created from wsdl2apex

public class AsyncWeatherRequestWebService2 {
public class GetCitiesByCountryResponse_elementFuture extends System.WebServiceCalloutFuture {
    public String getValue() {
        WeatherRequestWebService2.GetCitiesByCountryResponse_element response = (WeatherRequestWebService2.GetCitiesByCountryResponse_element)System.WebServiceCallout.endInvoke(this);
        return response.GetCitiesByCountryResult;
public class GetWeatherResponse_elementFuture extends System.WebServiceCalloutFuture {
    public String getValue() {
        WeatherRequestWebService2.GetWeatherResponse_element response = (WeatherRequestWebService2.GetWeatherResponse_element)System.WebServiceCallout.endInvoke(this);
        return response.GetWeatherResult;
public class AsyncGlobalWeatherSoap {
    public String endpoint_x = 'http://www.webservicex.net/globalweather.asmx';
    public Map<String,String> inputHttpHeaders_x;
    public String clientCertName_x;
    public Integer timeout_x;
    private String[] ns_map_type_info = new String[]{'http://www.webserviceX.NET', 'WeatherRequestWebService2'};
    public AsyncWeatherRequestWebService2.GetCitiesByCountryResponse_elementFuture beginGetCitiesByCountry(System.Continuation continuation,String CountryName) {
        WeatherRequestWebService2.GetCitiesByCountry_element request_x = new WeatherRequestWebService2.GetCitiesByCountry_element();
        request_x.CountryName = CountryName;
        return (AsyncWeatherRequestWebService2.GetCitiesByCountryResponse_elementFuture) System.WebServiceCallout.beginInvoke(
          new String[]{endpoint_x,
    public AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture beginGetWeather(System.Continuation continuation,String CityName,String CountryName) {
        WeatherRequestWebService2.GetWeather_element request_x = new WeatherRequestWebService2.GetWeather_element();
        request_x.CityName = CityName;
        request_x.CountryName = CountryName;
        return (AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture) System.WebServiceCallout.beginInvoke(
          new String[]{endpoint_x,


I am just testing this using the execute anonymous window

AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture GetWeatherRequestService;

 AsyncWeatherRequestWebService2.AsyncGlobalWeatherSoap GetWeatherRequest = new AsyncWeatherRequestWebService2.AsyncGlobalWeatherSoap();   

 Integer TIMEOUT_INT_SECS = 90;  
 Continuation cont = new Continuation(TIMEOUT_INT_SECS);
 cont.continuationMethod = 'processResponse';     

GetWeatherRequestService = GetWeatherRequest.beginGetWeather(cont, 'Paris','france'); 


and the error i am receiving is System.NullPointerException: Attempt to de-reference a null object pointing to return response.GetWeatherResult;

when i test the webservice using SOAPUI, it does return something.

so is this issue in the way i am calling the webservice? is the generated class missing something?

help please!

It is probably because of the "cont.continuationMethod = 'processResponse'; "

does it require a call back method?

public Object processResponse() {
result = GetWeatherRequestService.getValue();
return result;

  • could you please share where can I find a link or process to get the weather API, wsdl – Suresh Apr 28 '15 at 13:52
  • @Suri WSDL but I couldn't get it to import into Salesforce (because of the SOAP 1.2 stuff in there) Muriel, could you please share your WSDL? – bananka Apr 28 '15 at 14:28
  • 1
    Hi, webservicex.net/globalweather.asmx?WSDL – Muriel Apr 28 '15 at 14:58
  • t is probably because of the "cont.continuationMethod = 'processResponse'; " does it require a call back method? public Object processResponse() { result = GetWeatherRequestService.getValue(); return result; – Muriel Apr 28 '15 at 15:06
  • @Muriel : I have a very similar problem. When I try to invoke the class created from WSDL2Apex, it returns null value. I am trying to call it from workbench just like you. I believe you got this working. Can you explain how? I didn't follow the solution mentioned. – Kunal Shah Oct 27 '15 at 20:43

Wsdl2Apex now creates two sets of Apex classes for interacting with the SOAP based web service.

  • The first use WebServiceCallout.invoke and are synchronous. These are historically all that were generated.
  • The second use what is called a Continuation. These are new in Spring 15. See Make Long-Running Callouts from a Visualforce Page. It will use WebServiceCallout.beginInvoke and WebServiceCallout.endInvoke calls

For the purposes of testing the web service via anonymous apex you will want to use the former. It will have a name like WeatherRequestWebService2 based on your sample code.

E.g. (After adding Remote Sites setting for http://www.webservicex.net)

wwwWebservicexNet.GlobalWeatherSoap ws = new wwwWebservicexNet.GlobalWeatherSoap();


string weather = ws.GetWeather('Paris / Le Bourget', 'France');


<?xml version="1.0" encoding="utf-16"?>
  <Location>Paris / Le Bourget, France (LFPB) 48-58N 002-27E 65M</Location>
  <Time>Apr 28, 2015 - 07:00 PM EDT / 2015.04.28 2300 UTC</Time>
  <Wind> from the N (010 degrees) at 5 MPH (4 KT):0</Wind>
  <Visibility> greater than 7 mile(s):0</Visibility>
  <Temperature> 42 F (6 C)</Temperature>
  <DewPoint> 35 F (2 C)</DewPoint>
  <RelativeHumidity> 75%</RelativeHumidity>
  <Pressure> 30.15 in. Hg (1021 hPa)</Pressure>
  • thanks Daniel. so can you use a "continuation callout" from a trigger using @future(callout=true)? or would you simply use the synchronous callout from a @future trigger? – Muriel Apr 29 '15 at 8:52
  • You would use the synchronous version from a future context. As far as I've seen Continuations are only used from Visualforce. – Daniel Ballinger Apr 29 '15 at 9:07
  • @Muriel Great. Convention on Stack Exchange sites is to mark an accepted answer with the green check mark that appear by the voting buttons. This will indicate to others that a solution has been found. – Daniel Ballinger Apr 29 '15 at 19:30

Yes it requires callback method. You must return Continuation object in controller, let's assume that you have method callWeatherWebService() in controller, looking like this:

public Object callWeatherWebService() {
    Continuation cont = new Continuation(TIMEOUT_INT_SECS);
    cont.continuationMethod = 'processResponse';
    GetWeatherRequestService = GetWeatherRequest.beginGetWeather(cont, 'Paris','france');
    return cont;

Then you have to provide callback method, note that result must public field in your controller:

public void processResponse() {
    result = GetWeatherRequestService.getValue();

When webservice returns results, callback method is invoked and then your page is refreshed with new value (result).

  • @ mischczu: this would work fine from a visualforce page. now if i want to call this from trigger with @Future(callout=true), i am not sure how this is supposed to work. Basically, the trigger calls a global class with a public static void. This public static void is suposed to call the webservice (that bit works ok), but I am having problem with the call back. – Muriel Apr 29 '15 at 8:31
  • OK, so I would use synchronous version from trigger with future, because I don't think that Continuation object is supported in triggers. It requires special handling, which is provided by Controller. Now I've seen that earlier @Daniel Ballinger suggested that :) – mischczu Apr 29 '15 at 9:28

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