public SOAPEnvelope(InputStream input) throws SAXException {
        InputSource is = new InputSource(input);
        header = new SOAPHeader(this, soapConstants); // soapConstants = null!
        DeserializationContext dser = null ;
        AxisClient     tmpEngine = new AxisClient(new NullProvider());
        MessageContext msgContext = new MessageContext(tmpEngine);
        dser = new DeserializationContextImpl(is, msgContext,
                                              Message.REQUEST, this );
        dser.parse();
    }