Document: createComment(String data)
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Comment; import org.w3c.dom.Document; 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")); Comment comment = doc.createComment("invalid -- comment"); boolean validComment = comment.getNodeValue().indexOf("--") < 0; } }