XML file not getting update after modification using JDOM

Question

i am trying to update elements in xml file using jdom, but somehow after whole operation file is not getting updated. below is my code:+

public int editServer(String[] server) {
    int response = 0;
    int validate = 0;
    try {
        File inputFile = new File(fileName);
        saxBuilder = new SAXBuilder();
        document = saxBuilder.build(inputFile);
        classElement = document.getRootElement();
        List<Element> voiceServers = classElement.getChildren();
        for (int temp = 0; temp < voiceServers.size(); temp++) {

            Element vServer = voiceServers.get(temp);
            serverName = vServer.getChild("ServerName").getText();
            type = vServer.getChild("Type").getText();
            String metaData[] = { "ServerName", "IP", "Port", "UserName", "Password", "DataBase", "Type", "Status" };
            if (serverName.equalsIgnoreCase(server[0].toString()) && type.equalsIgnoreCase(server[6].toString())) {
                // 2 : deleted
                validate = validateServer(server);
                if (server.length == metaData.length && validate != 1) {
                    for (int i = 1; i < metaData.length; i++) {
                        System.out.println("Previous Value : " + vServer.getChild(metaData[i]).getText());
                        vServer.getChild(metaData[i]).setText(server[i]);
                        System.out.println("New Value : " + vServer.getChild(metaData[i]).getText());
                    }
                    System.out.println("DOne Save...");
                    break;
                }
                // vServer.getChild("ServerName").setText(text)

            } else {
                response = 500;
            }
        }
        FileWriter writer = new FileWriter(fileName);
        XMLOutputter outputter = new XMLOutputter();
        outputter.setFormat(Format.getPrettyFormat());
        outputter.output(document, writer);
        response = 2;
    } catch (JDOMException e) {
        e.printStackTrace();
    } catch (IOException ioe) {
        ioe.printStackTrace();
    }
    return response;
}

and below is console response which i am printing before and after values of child.