Help, Invoking webservice exported by ofbiz fails

[李明洋]

*The exported web service is defined as follow:*

<service name="test.add" engine="java" auth="true" export="true"
     location="org.aries.erp.test.TestServices"
     invoke="add">
    <attribute name="a" type="Integer" mode="IN" optional="false"
></attribute>
    <attribute name="b" type="Integer" mode="IN"
optional="false"></attribute>
    <attribute name="result" type="Integer" mode="OUT"
optional="false"></attribute>
    </service>

*the webservice client code is *


public static void main(String[] args) {
        Integer output = 0;
String endpoint, username, password;
try{
            endpoint = "http://localhost:8080/webtools/control/SOAPService";;
            username="admin";
            password="ofbiz";
            Call call = (Call) new Service().createCall();
            call.setTargetEndpointAddress(new URL (endpoint));
            call.setOperationName(new
javax.xml.namespace.QName("test.add"));
            Integer a = 3;
            Integer b = 5;
            call.addParameter("a", org.apache.axis.Constants.XSD_INT,
javax.xml.rpc.ParameterMode.IN);
            call.addParameter("b", org.apache.axis.Constants.XSD_INT,
javax.xml.rpc.ParameterMode.IN);
            call.addParameter("login.username",
org.apache.axis.Constants.XSD_STRING, javax.xml.rpc.ParameterMode.IN);
            call.addParameter("login.password",
org.apache.axis.Constants.XSD_STRING, javax.xml.rpc.ParameterMode.IN);
            call.setReturnType(org.apache.axis.Constants.SOAP_INTEGER);
            Object response = call.invoke(
                    new Object[]{
                        a,
                        b,
                        username,
                        password}
                    );
            output =  (Integer) response;
            try{
                    System.out.println(output);
            }
            catch(Exception e){
                    e.printStackTrace();
            }
}catch(Exception e){
e.printStackTrace();
}
return;
    }

 but it throws a exception : *org.xml.sax.SAXException: SimpleDeserializer
encountered a child element, which is NOT expected, in something it was
trying to deserialize.*
*
*
Could you give me some help;

thanks