that isnt valid xml ... also, most parsers wont allow you to change the tag name. you could consider using xsl to transform a document into a what you need.

the following has an example of how to get things done with xsl. http://www.exampledepot.com/egs/javax.xml.transform/BasicXsl.html

having re-read this, it may be that you only want to update the text content, i.e. 'xyz' in your example? if that is the case, that is fairly straightforward. example in this case is derived from http://javaalmanac.com/

    import java.io.*;
    import javax.xml.parsers.*;
    import org.w3c.dom.*;
    import org.xml.sax.*;
   
    public class BasicDom {
        public static void main(String[] args) {
            Document doc = parseXmlFile("infilename.xml", false);
            // Obtain a node
            Element element = (Element)doc.getElementsByTagName("name").item(0);
            // set the textContent
            element.setTextContent("my new text");
            // write to a file
            // refer to http://java.sun.com/webservices/jaxp/dist/1.1/docs/tutorial/xslt/2_write.html
        }
   
        // Parses an XML file and returns a DOM document.
        // If validating is true, the contents is validated against the DTD
        // specified in the file.
        public static Document parseXmlFile(String filename, boolean validating) {
            try {
                // Create a builder factory
                DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                factory.setValidating(validating);
   
                // Create the builder and parse the file
                Document doc = factory.newDocumentBuilder().parse(new File(filename));
                return doc;
            } catch (SAXException e) {
                // A parsing error occurred; the xml input is not valid
            } catch (ParserConfigurationException e) {
            } catch (IOException e) {
            }
            return null;
        }
    }

yes sorry i mistyped it, i just want to update the value i.e xyz.

the ccorrect xml is

<name>xyz</name>

element.setTextContent("my new text"); does not seem to be working. It does not do anything.

replace
     element.setTextContent("my new text");

with the following:

Node parent = element.getParentNode();
parent.removeChild(element);
element.setTextContent("my new text");
parent.appendChild(element);

i get this error

GetRootNode.java:43: cannot resolve symbol
symbol  : method setTextContent (java.lang.String)
location: interface org.w3c.dom.Element
element.setTextContent("my new text");

can you post all of your code?

import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;
import java.net.URL;

import java.lang.Object;
import java.io.IOException;
import java.io.*;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Text;

public class GetRootNode{
  public static void main(String[] args) {
    try{
     BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

      File file = new File("filename.xml");
      if (file.exists()){
        DocumentBuilderFactory fact = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = fact.newDocumentBuilder();
        Document doc = builder.parse("filename.xml");
        Node node = doc.getDocumentElement();
        String root = node.getNodeName();
        System.out.println("Root Node: " + root);            
      Element element = (Element)doc.getElementsByTagName("NAME").item(0);
      
Node parent = element.getParentNode();
parent.removeChild(element);
element.setTextContent("my new text");
parent.appendChild(element);

      System.out.println("Node Name"+ element.getNodeName());
            
      TransformerFactory tranFactory = TransformerFactory.newInstance();
    Transformer aTransformer = tranFactory.newTransformer();
   
    Source src = new DOMSource(doc);
   
    javax.xml.transform.Result dest = new StreamResult(file);
    aTransformer.transform(src, dest);
              System.out.println("Changed Element: " + element);
                    System.out.println("ya "+element.getChildNodes().getLength());
                    System.out.println("no "+element.getChildNodes());
                              
      }
      else{
        System.out.println("File not found!");
      }
    }
    catch(Exception e){}
  }
}

you are probably using java 1.4 ... try element.setNodeValue("my new text"); instead of element.setTextContent("my new text");

And this <NAME> tag is in the root node. If i ahev to update a tag value that is within a tag, how do i do it?

<ADDRESS>
         <CITY>
                      abc city
         </CITY>
</ADDRESS>

assuming that their is only one node with that name, do
    getElementsByTagName("NAME").item(0);
if there are more, you will have to iterate over them
read http://java.sun.com/j2se/1.4.2/docs/api/org/w3c/dom/Element.html, specifically getElementsByTagName()

ok wil try that for node within node however

element.setNodeValue("my new text");  does not work. I tried that yesterday also. is there any other work around?

an alternative would be to try the method createTextNode() [http://www.exampledepot.com/egs/org.w3c.dom/AddText.html, http://java.sun.com/j2se/1.4.2/docs/api/org/w3c/dom/Document.html].

Also, if its possible, can you upgrade to java 1.5?

so if i try to use this it works but it does not replace the old value. It only appends to the existing value. Can we replace the old value using this?


 Text text = doc.createTextNode("test123");
  text.setData("hello");
  element.appendChild(text);

Element element = (Element)doc.getElementsByTagName("NAME").item(0);
Node parent = element.getParentNode();
parent.removeChild(element);
Text text = doc.createTextNode("test123");
text.setData("hello");
parent.appendChild(text);

it is removing the tag but not putting it back again.

is this what you want?

Element element = (Element)doc.getElementsByTagName("NAME").item(0);
Node parent = element.getParentNode();
parent.removeChild(element);
Text text = doc.createTextNode(element.getTagName()); // set name to be old name ...
text.setData("hello");
parent.appendChild(text);

the only problem with that is now if the node that you are setting the text to contains other nodes, they will disappear ... if you insist on using java 1.4, you should download  Xerces-J and place the libraries in your <java-home>\lib\endorsed directory...

Then use the original method that i stated above, namely setTextContent ...

cool let me try that thanks a lot for all the info.

so is there somethign i need to importafter puting these xerces libraries in the java home?