hi there,
how can I change string to xml and vise verse in java, in addition how can I add values to xml according to element name ,
I can imagine something like "setValue(elementName, the value) ; as we are using in java,

any suggestions any help , please!
thanks in advance

You might want to look into the Java XML API, W3C DOM API and its implementations like Xerces. The Xerces XML parsing library comes bundled with your Java runtime. A simple Xerces program:

public class Test {

   public static void main(final String[] args) throws Exception {
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();      
      DocumentBuilder builder = factory.newDocumentBuilder();
      System.out.println(factory + "\n" + builder);
      InputSource in = new InputSource(new StringReader(
            "<?xml version='1.0'?><root><child value='1'/></root>"));
      // The doc now contains the entire XML hierarchy
      Document doc = builder.parse(in);
   }

}

BTW, if all you need to do is manipulate your XML files in memory, go for a Java specific solution like JDOM.