MainClass.java

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class MainClass {
  public static void main(String[] args) throws Exception{
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();

    Document document = db.newDocument();

    Element book = document.createElement("book"); 

    //book.setAttribute("xmlns:hello", "hello/world");           
    //book.setAttribute("hello:id", "javanut4");           

    // This line is equivalent to the two lines above
    book.setAttributeNS("hello/world", "hello:id", "javanut4");           

    System.out.println("Attribute count: " + book.getAttributes().getLength());
    System.out.println("Has hello:id: " + book.hasAttribute("hello:id"));

    document.appendChild(book);                    

    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer transformer = tf.newTransformer();

    DOMSource source = new DOMSource(document);          
    StreamResult result = new StreamResult(System.out);  

    transformer.transform(source, result);
  }
}