Here you can find the source of addDays(Date start, int days)
public static Date addDays(Date start, int days)
//package com.java2s; import java.util.Calendar; import java.util.Date; public class Main { public static Date addDays(Date start, int days) { Calendar now = Calendar.getInstance(); now.setTime(start);/*from w w w.jav a2s . c o m*/ Calendar working; working = (Calendar) now.clone(); working.add(Calendar.DAY_OF_YEAR, days); return working.getTime(); } }