sjsxp issue 28 and 34 were merged into JAXP, but not integrated into JDK. Refer to the original issues and comment of the original merge:
6419687:XMLCOnstants.NULL_NS_URI is not available in a pure JDK 1.4 environment, use literal; sjsxp-issue-28:A reference to a property manager must be passed when constructing a writer instance; sjsxp-issue-34 pop namespace context when closing an EmptyElement; sjsxp revision 1.10:Removed call to flush() when the underlying output stream is requested via get(). We'll let the application worry about flushing the stream to avoid unwanted HTTP chunking while running inside a container.