I have a schema that defines an element ("payload") as "anyType". My
code generator defines the property as type Object as it should. When
I marshal the message JAXB creates XML along the lines of the
following:
<ns2:MessageToAccept
xmlns:ns2="
http://soa.finra.org/member/common/ESBToWebServiceClientV02/
" xmlns:ns4="
http://soa.finra.org/ufi/ufi-commandV01"
xmlns:ns3="
http://soa.finra.org/ufi/ufi-responseV01"
xmlns:ns5="
http://soa.finra.org/member/common/common-messagesV01">
<ns4:ufiCommand>
<payload xsi:type="ns4:UfiCommandPayload"
xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance">
...
</payload>
</ns4:ufiCommand>
</ns2:MessageToAccept>
Note that the "payload" element has the xsi:type attribute with a value
of "ns4:UfiCommandPayload". ns4 is a namespace defined in the root
element. I assume this attribute is used as a hint to JAXB when
unmarshalling.
The problem is that include a namespace in an attribute value is
nothing XML cares about. In my case the service I call copies the
payload and returns it to me as part of the response. When JAXB gets
hold of it to unmarshal, that ns4:UfiCommandPayload is used as a
namespace which is no longer present.
Put another way, JAXB put the namespace alias in an attribute value
with the namespace itself defined elsewhere. The service I called
copied the payload out of my request and returned it in the response.
However it didn't need to copy the ns4 namespace because there are no
elements in that namespace used. When JAXB takes the attribute value
and tries to look up a namespace which is not defined in the response.
I'm not sure what to do at this point. I understand that JAXB needs
hints on how to unmarshal a document. Using a namespace in that hint
that isn't defined in the element itself is probably not a good idea.
I guess if I could get JAXB to define the namespace in the payload
element, that should work. Is it possible?
(Note: I tried adding XmlElement(type = UfiCommandPayload) to the
payload property. That removes the xsi:type attribute from the request
xml but there are other classes that inherit the Message class that has
the payload property. JAXB can't always unmarshal payload as
UfiCommandPayload.)