Here you can find the source of setDayOfMonth(Date d, int date)
public static Date setDayOfMonth(Date d, int date)
//package com.java2s; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.Locale; import java.util.TimeZone; public class Main { public static Date setDayOfMonth(Date d, int date) { Calendar c = getCalendar(); c.setTime(d);// w w w . j a v a2 s .com c.set(Calendar.DAY_OF_MONTH, date); return (c.getTime()); } /** * month ranges from 1 to 12 (not 0 to 11) */ private static Calendar getCalendar() { return (getCalendar(null, null)); } private static Calendar getCalendar(TimeZone timeZone, Locale locale) { if (timeZone == null) timeZone = TimeZone.getDefault(); if (locale == null) locale = Locale.getDefault(); Calendar c = new GregorianCalendar(timeZone, locale); return (c); } public static Date setTime(Date d, long time) { d.setTime(time); return (d); } public static long getTime() { Date d = new Date(); return (d.getTime()); } public static long getTime(Date d) { return (d.getTime()); } }