Java Tutorial/XML/Processing Instruction

Adding a Processing Instruction to a DOM Document

import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
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"));
    // Add a PI at the beginning of the document
    Element element = doc.getDocumentElement();
    ProcessingInstruction pi = doc.createProcessingInstruction("target", "instruction");
    element.getParentNode().insertBefore(pi, element);

  }
}

Find elements and add a child PI

import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
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();
    ProcessingInstruction pi = doc.createProcessingInstruction("target", "instruction");
    NodeList list = doc.getElementsByTagName("entry");
    for (int i = 0; i < list.getLength(); i++) {
      element = (Element) list.item(i);
      pi = doc.createProcessingInstruction("target", "instruction=" + i);
      element.appendChild(pi);
    }
  }
}