怎么j2ME中想用Timer和TimeTask来实现提示信息功能

public class PasswordModifyForm extends Form implements CommandListener {
    // -------信息提示
    private String msg = "";

    private int pos;

    private static PasswordModifyForm instance;

    private static TextField newPassword = null;

    private static TextField newPasswordTwo = null;

    private static Command ok = new Command("确定", 4, 1);

    private static Command back = new Command("返回", 2, 1);

    private PasswordModifyForm() {
        super(" ");

        // 请输入描述信息
        newPassword = new TextField("输入密码", "", 12, 0);
        newPasswordTwo = new TextField("再输一次", "", 12, 0);

        append(newPassword);
        append(newPasswordTwo);

        addCommand(ok);
        addCommand(back);
        setCommandListener(this);
    }

    public static PasswordModifyForm getInstance() {
        if (instance == null)
            instance = new PasswordModifyForm();
        return instance;
    }

    public void commandAction(Command c, Displayable d) {
        String newp = "", newPTwo = "";
        newp = newPassword.getString();
        newPTwo = newPasswordTwo.getString();

        if (c == ok) {
            synchronized (this) {
            // -----密码
            if (DateTool.isEmpty(newp) || DateTool.isEmpty(newPTwo)) {
                // ----密码不能为空
            
                    msg = "密码不能为空!";
                    StringItem si = new StringItem(msg, "");

                    pos = this.append(si);

                    // ----------
                    Timer timer = new Timer();
                    timer.schedule(new TimerTask() {
                        public void run() {         

                            if (!DateTool.isEmpty(msg)) {
                                delete(pos);
                                msg = "";                         
                            }

                        }
                    }, 500);
                }
                 
            }
        } else if (c == back) {
            App.showBefore();
        }
    }
}