SOAP C# Server with Java client null return

Question

I would like to check SOAP interoperability between distinct platforms; I am a Java programmer and do not know C# in particular.

What have I managed to do in C#:

The transfer Object:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Xml.Serialization;

[XmlRoot]
public class Pack
{
    private int id;
    private string name;

    public Pack()
    {   
    }

    public Pack(int anId, string aName)
    {
        this.id = anId;
        this.name = aName;
    }

    public void setId(int anId)
    {
        this.id = anId;
    }

    public int getId()
    {
        return id;
    }

    public void setName(string aName)
    {
        this.name = aName;
    }

    public string getName()
    {
        return name;
    }
}

The Web Service:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Xml.Serialization;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class PackWS : System.Web.Services.WebService
{
    private Dictionary<int, Pack> dictionary;

    public PackWS()
    {
        dictionary = new Dictionary<int, Pack>();
    }

    [WebMethod]
    [XmlInclude(typeof(String))]
    public String getName()
    {
        return "Goodbye world!";
    }

    [WebMethod]
    [XmlInclude(typeof(Pack))]
    public void addPackage(Pack package)
    {
       dictionary.Add(package.getId(), package);
    }

    [WebMethod]
    [XmlInclude(typeof(Pack))]
    public Pack getPackage(int id)
    {
        return dictionary[id];
    }
}

The project builds and publishes the wsdl at the specified URI. I have added a Java client part:

The Transfer Object:

package user;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Pack {
    private int id;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

The Interface:

package user;

import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;

@WebService(targetNamespace = "http://tempuri.org/",
        portName = "PackWSSoap",
        wsdlLocation = "http://localhost:57265/Service.asmx?wsdl",
        serviceName = "PackWS")
@SOAPBinding(style = SOAPBinding.Style.RPC)
public interface PackWSSoap {
    void addPackage(Pack pack);
    Pack getPackage(int id);
    String getName();
}

The Service

package user;

import javax.xml.namespace.QName;
import javax.xml.ws.Service;
import java.net.MalformedURLException;
import java.net.URL;

public class PackageClient {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://localhost:57265/Service.asmx?wsdl");
            QName qName = new QName("http://tempuri.org/", "PackWS");

            Service service = Service.create(url, qName);

            PackWSSoap packWS = service.getPort(PackWSSoap.class);

            System.out.println(packWS.getName());//null here

            packWS.addPackage(getPack());//C# exception here

            System.out.println(packWS.getPackage(getPack().getId()));//unreachable 


        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }

    static Pack getPack() {
        return new Pack(){{
            setId(2);
            setName("name");
        }
        };
    }
}

When calling the getName() method, it should return a simple String, but it returns null. When trying to add a package by calling addPackage(pack) I receive an exception from C# on the client, in Java:

Exception in thread "main" javax.xml.ws.soap.SOAPFaultException: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at PackWS.addPackage(Pack package) in f:\DS Projects\ds5\NET\App_Code\PackWS.cs:line 38
   --- End of inner exception stack trace ---
    at com.sun.xml.ws.fault.SOAP11Fault.getProtocolException(SOAP11Fault.java:163)
    at com.sun.xml.ws.fault.SOAPFaultBuilder.createException(SOAPFaultBuilder.java:94)
    at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:236)
    at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:206)
    at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:103)
    at $Proxy18.addPackage(Unknown Source)
    at user.PackageClient.main(PackageClient.java:25)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

I do not believe to be anything wrong with the communication since the exception is passed well; but I believe I did not add something to the .NET server. Any help would be appreciated and sorry for the long post.

Here is the WSDL:

<wsdl:definitions xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tm="http://microsoft.com/wsdl/mime/textMatching/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/" xmlns:tns="http://tempuri.org/" xmlns:s="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" xmlns:http="http://schemas.xmlsoap.org/wsdl/http/" targetNamespace="http://tempuri.org/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/">
<wsdl:types>
<s:schema elementFormDefault="qualified" targetNamespace="http://tempuri.org/">
<s:element name="getName">
<s:complexType/>
</s:element>
<s:element name="getNameResponse">
<s:complexType>
<s:sequence>
<s:element minOccurs="0" maxOccurs="1" name="getNameResult" type="s:string"/>
</s:sequence>
</s:complexType>
</s:element>
<s:element name="addPackage">
<s:complexType>
<s:sequence>
<s:element minOccurs="1" maxOccurs="1" name="package" nillable="true" type="tns:Pack"/>
</s:sequence>
</s:complexType>
</s:element>
<s:complexType name="Pack"/>
<s:element name="addPackageResponse">
<s:complexType/>
</s:element>
<s:element name="getPackage">
<s:complexType>
<s:sequence>
<s:element minOccurs="1" maxOccurs="1" name="id" type="s:int"/>
</s:sequence>
</s:complexType>
</s:element>
<s:element name="getPackageResponse">
<s:complexType>
<s:sequence>
<s:element minOccurs="1" maxOccurs="1" name="getPackageResult" nillable="true" type="tns:Pack"/>
</s:sequence>
</s:complexType>
</s:element>
</s:schema>
</wsdl:types>
<wsdl:message name="getNameSoapIn">
<wsdl:part name="parameters" element="tns:getName"/>
</wsdl:message>
<wsdl:message name="getNameSoapOut">
<wsdl:part name="parameters" element="tns:getNameResponse"/>
</wsdl:message>
<wsdl:message name="addPackageSoapIn">
<wsdl:part name="parameters" element="tns:addPackage"/>
</wsdl:message>
<wsdl:message name="addPackageSoapOut">
<wsdl:part name="parameters" element="tns:addPackageResponse"/>
</wsdl:message>
<wsdl:message name="getPackageSoapIn">
<wsdl:part name="parameters" element="tns:getPackage"/>
</wsdl:message>
<wsdl:message name="getPackageSoapOut">
<wsdl:part name="parameters" element="tns:getPackageResponse"/>
</wsdl:message>
<wsdl:portType name="PackWSSoap">
<wsdl:operation name="getName">
<wsdl:input message="tns:getNameSoapIn"/>
<wsdl:output message="tns:getNameSoapOut"/>
</wsdl:operation>
<wsdl:operation name="addPackage">
<wsdl:input message="tns:addPackageSoapIn"/>
<wsdl:output message="tns:addPackageSoapOut"/>
</wsdl:operation>
<wsdl:operation name="getPackage">
<wsdl:input message="tns:getPackageSoapIn"/>
<wsdl:output message="tns:getPackageSoapOut"/>
</wsdl:operation>
</wsdl:portType>
<wsdl:binding name="PackWSSoap" type="tns:PackWSSoap">
<soap:binding transport="http://schemas.xmlsoap.org/soap/http"/>
<wsdl:operation name="getName">
<soap:operation soapAction="http://tempuri.org/getName" style="document"/>
<wsdl:input>
<soap:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="addPackage">
<soap:operation soapAction="http://tempuri.org/addPackage" style="document"/>
<wsdl:input>
<soap:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="getPackage">
<soap:operation soapAction="http://tempuri.org/getPackage" style="document"/>
<wsdl:input>
<soap:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap:body use="literal"/>
</wsdl:output>
</wsdl:operation>
</wsdl:binding>
<wsdl:binding name="PackWSSoap12" type="tns:PackWSSoap">
<soap12:binding transport="http://schemas.xmlsoap.org/soap/http"/>
<wsdl:operation name="getName">
<soap12:operation soapAction="http://tempuri.org/getName" style="document"/>
<wsdl:input>
<soap12:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap12:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="addPackage">
<soap12:operation soapAction="http://tempuri.org/addPackage" style="document"/>
<wsdl:input>
<soap12:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap12:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="getPackage">
<soap12:operation soapAction="http://tempuri.org/getPackage" style="document"/>
<wsdl:input>
<soap12:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap12:body use="literal"/>
</wsdl:output>
</wsdl:operation>
</wsdl:binding>
<wsdl:service name="PackWS">
<wsdl:port name="PackWSSoap" binding="tns:PackWSSoap">
<soap:address location="http://localhost:57265/Service.asmx"/>
</wsdl:port>
<wsdl:port name="PackWSSoap12" binding="tns:PackWSSoap12">
<soap12:address location="http://localhost:57265/Service.asmx"/>
</wsdl:port>
</wsdl:service>
</wsdl:definitions>

Answer 1

Web services in .NET don't maintain session state between requests. When you initialize the dictionary, it is only there for the duration of that particular request. On subsequent requests, it's null again, hence the exception you're getting.

If you want to implement a service like this, using an object that persists between requests, you can use Application as a shared store. It looks a little ugly because you have to type cast when you access it, though.

Initialization:

Application["dictionary"] = new Dictionary<int, Pack>();

Adding:

((Dictionary<int, Pack>)Application["dictionary"]).Add(package.getId(), package);

Reading:

return ((Dictionary<int, Pack>)Application["dictionary"])[id];

More information about the Application store - an instance of HttpApplicationState - is available at http://msdn.microsoft.com/en-us/library/system.web.httpapplicationstate.aspx

Answer 2

If it is not strictly necessary, I would never use soap. I would recommend you to use a REST web service putting in the body JSON objects.