XML Java Tutorial

import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamWriter;
public class DefaultNamespaceStreamOutput {
  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();
  }
}