Add a comment at the beginning of the document : Comment « XML « Java Tutorial

1. Java Tutorial
2. XML
3. Comment

import java.io.File;

import javax.xml.parsers.DocumentBuilderFactory;

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

public class Main {
  public static void main(String[] argv) throws Exception {

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    factory.setValidating(true);

    factory.setExpandEntityReferences(false);

    Document doc = factory.newDocumentBuilder().parse(new File("filename"));

    Element element = doc.getDocumentElement();
    Comment comment = doc.createComment("A Document Comment");
    element.getParentNode().insertBefore(comment, element);

  }
}