question: public void startDocument ( ) throws ODataRenderException { outputStream = new ByteArrayOutputStream ( ) ; try { xmlWriter = xmlOutputFactory . createXMLStreamWriter ( outputStream , UTF_8 . name ( ) ) ; xmlWriter . writeStartDocument ( UTF_8 . name ( ) , XML_VERSION ) ; xmlWriter . setPrefix ( METADATA , ODATA_METADATA_NS ) ; } catch ( XMLStreamException e ) { LOG . error ( "Not possible to start stream XML" ) ; throw new ODataRenderException ( "Not possible to start stream XML: " , e ) ; } }
target:  Start the XML stream document by defining things like the type of encoding, and prefixes used. It needs to be used before calling any write method.