reading and writing values to xml doc using Java

Hi,

Could some on eplease help me in achieving this? I need to read some nodes from an xml doc and write some values to those nodes using Java.

I'm attaching the sample xml and my Ajava code below.
Any suggestions please??

xml code:
<?xml version="1.0"?>
<TestPreview>
<TestCard>
<SelectedItem>1</SelectedItem>
<Salutation>Dear Test</Salutation>
<MessageBody xml:space="preserve"> Test Message</MessageBody>
<MessageFont>Arial</MessageFont>
<MessageSize>12</MessageSize>
<MessageColor>black</MessageColor>
<IdNo>12345</IdNo>
</TestCard>
</TestPreview>

Java Code:
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

DocumentBuilder builder = factory.newDocumentBuilder();
BufferedInputStream bin = null;
bin = new BufferedInputStream( new File(previewcard.xml));
Document document = builder.parse(bin);
NodeList nl = document.getElementsByTagName("*");
for(int i=0;i<nl.getLength();i++){
Node n = (Node)nl.item(i);
n.getNodeValue();
n.setNodeValue("test");
}


Best Regards,
Amar.