Here you can find the source of setToBeginningOfDay(Calendar cal)
public static Calendar setToBeginningOfDay(Calendar cal)
//package com.java2s; /**// w w w .ja va 2s .com * * Copyright (c) 2005-2012. Centre for Research on Inner City Health, St. Michael's Hospital, Toronto. All Rights Reserved. * This software is published under the GPL GNU General Public License. * This program 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 2 * of the License, or (at your option) any later version. * * This program 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 this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * This software was written for * Centre for Research on Inner City Health, St. Michael's Hospital, * Toronto, Ontario, Canada */ import java.util.Calendar; public class Main { /** * This method will set the calenders hour/min/sec//milliseconds all to 0. */ public static Calendar setToBeginningOfDay(Calendar cal) { cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); // force calculation / materialisation of actual time. cal.getTimeInMillis(); return (cal); } }