Prefix is null when using client stubs - soap

Question

I had to use axis to generate stubs because the SOAP I am working with uses RPC. After setting up the code to post I am receiving the below stack trace. If anyone has had this issue please help. From using the debug tool in Eclipse I can see that Axis is using default prefixes, but the issue is that one of the prefixes it uses has already been used so it returns null. Does anyone know why this may be happening?
AxisFault
faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException
faultSubcode:
faultString: java.io.IOException: java.io.IOException: Non nillable element 'prefix' is null.
faultActor:
faultNode:
faultDetail:
{http://xml.apache.org/axis/}stackTrace:java.io.IOException: java.io.IOException: Non nillable element 'prefix' is null.
at org.apache.axis.encoding.ser.BeanSerializer.serialize(BeanSerializer.java:275)
at org.apache.axis.encoding.SerializationContext.serializeActual(SerializationContext.java:1504)
at org.apache.axis.encoding.SerializationContext.serialize(SerializationContext.java:980)
at org.apache.axis.encoding.SerializationContext.outputMultiRefs(SerializationContext.java:1055)
at org.apache.axis.message.SOAPBody.outputImpl(SOAPBody.java:145)
at org.apache.axis.message.SOAPEnvelope.outputImpl(SOAPEnvelope.java:478)
at org.apache.axis.message.MessageElement.output(MessageElement.java:1208)
at org.apache.axis.client.Call.invoke(Call.java:2757)
at org.apache.axis.client.Call.invoke(Call.java:2443)
at org.apache.axis.client.Call.invoke(Call.java:2366)
at org.apache.axis.client.Call.invoke(Call.java:1812)

Answer 1

Though that this question is not answered after one year I thought that it might help you since you are working with RPC and probably a legacy system.
In your generated client stub with Apache Axis under packaging that ends with "_xsd" where the Objects of the web service provider are created open classes one by one.
Somewhere in the middle of the class you will find a static block code like this:
static {
typeDesc.setXmlType(...);
org.apache.axis.description.ElementDesc elemField = new org.apache.axis.description.ElementDesc();
elemField.setFieldName("prefix");
elemField.setXmlName(new javax.xml.namespace.QName("", "prefix"));
elemField.setXmlType(new javax.xml.namespace.QName("http://www.w3.org/2001/XMLSchema", "string"));
elemField.setNillable(false);
typeDesc.addFieldDesc(elemField);
}
just change the value of nillable to true like this:
elemField.setNillable(true);
You should repeat this action for all classes and all fields of those classes if they do not match with their corresponding values in your WSDL (i.e. based on the definition of your WSDL they are nullable).
I've noticed that Apache Axis 1.2 - 1.4 automatically makes attributes not 'nillable' by default. I don't know why is this the case but I think this is the solution.