Java tutorial
import javax.xml.stream.XMLOutputFactory; import javax.xml.stream.XMLStreamWriter; public class Main { public static void main(String[] args) throws Exception { XMLOutputFactory outputFactory = XMLOutputFactory.newInstance(); XMLStreamWriter writer = outputFactory.createXMLStreamWriter(System.out); writer.setDefaultNamespace("http://www.example.com/ns1"); writer.writeStartElement("http://www.example.com/ns1", "sample"); writer.writeDefaultNamespace("http://www.example.com/ns1"); writer.writeEmptyElement("inner"); writer.setDefaultNamespace("http://www.example.com/ns2"); writer.writeStartElement("http://www.example.com/ns2", "inner2"); writer.writeDefaultNamespace("http://www.example.com/ns2"); writer.writeNamespace("ns1", "http://www.example.com/ns1"); writer.writeEmptyElement("http://www.example.com/ns1", "inner"); writer.writeEndDocument(); writer.flush(); } }