Here you can find the source of addDay(Date date, String pattern, int num)
public static String addDay(Date date, String pattern, int num)
//package com.java2s; //License from project: LGPL import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; public class Main { public static String addDay(Date date, String pattern, int num) { SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern); Calendar calender = Calendar.getInstance(); calender.setTime(date);/*ww w . ja v a 2 s .c o m*/ calender.add(Calendar.DATE, num); return simpleDateFormat.format(calender.getTime()); } }