DouKaku?

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Sample204 {
    private static final DateFormat FORMAT = new SimpleDateFormat("yyyyMMddHHmmss");

    public static String dateEx(String time, int seconds) throws ParseException {
        Date date = FORMAT.parse(time);
        return dateEx(date, seconds);
    }
    public static String dateEx(int seconds) {
        return dateEx(new Date(), seconds);
    }

    private static String dateEx(Date date, int seconds) {
        Calendar cal = Calendar.getInstance();
        cal.setTime( date );
        cal.add(Calendar.SECOND, seconds);
        return FORMAT.format(cal.getTime());
    }


    public static void main(String[] args) {
        try {
            System.out.println(dateEx("20080827235925",40));
            System.out.println(dateEx(0));
        } catch (ParseException ex) {
            ex.printStackTrace();
        }
    }
}