Here you can find the source of getDay(Date date)
public static int getDay(Date date)
//package com.java2s; /**// w w w .j a v a2 s.c om * This file is part of jpa-cert application. * * Jpa-cert is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * Jpa-cert is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with jpa-cert; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; public class Main { public static int getDay(Date date) { return newCalendar(date).get(Calendar.DAY_OF_MONTH); } public static int get(int field, Date date) { Calendar calendar = newCalendar(date); return calendar.get(field); } private static Calendar newCalendar(Date date) { Calendar calendar = new GregorianCalendar(); calendar.setTime(date); return calendar; } public static Date setTime(Date date, int hourOfDay, int minute, int second) { Calendar calendar = newCalendar(date); calendar.set(Calendar.HOUR_OF_DAY, hourOfDay); calendar.set(Calendar.MINUTE, minute); calendar.set(Calendar.SECOND, second); return calendar.getTime(); } }