import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
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"));
NodeList list = doc.getElementsByTagName("entry");
Element element = (Element) list.item(0);
Element dup = (Element) element.cloneNode(true);
element.getParentNode().insertBefore(dup, element.getNextSibling());
}
}