import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
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.getElementById("key1");
element.setAttribute("newAttrName", "attrValue");
element.setAttribute("newAttrName", "<>&\"'");
element.removeAttribute("value");
boolean has = element.hasAttribute("value"); // true
String attrValue = element.getAttribute("value"); // mydefault
}
}