Here you can find the source of isYesterday(Date date)
public static boolean isYesterday(Date date)
//package com.java2s; /*/*from w ww . j ava2 s .c o m*/ * Copyright (C) 2005 - 2014 TIBCO Software Inc. All rights reserved. * http://www.jaspersoft.com. * * Unless you have purchased a commercial license agreement from Jaspersoft, * the following license terms apply: * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.util.Calendar; import java.util.Date; public class Main { public static boolean isYesterday(Date date) { return isSameDay(date, rollDay(new Date(), -1)); } public static boolean isSameDay(Date date1, Date date2) { if (date1 == null || date2 == null) { throw new IllegalArgumentException("The dates must not be null"); } Calendar cal1 = Calendar.getInstance(); cal1.setTime(date1); Calendar cal2 = Calendar.getInstance(); cal2.setTime(date2); return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) && cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) && cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR)); } private static Date rollDay(Date date, long amount) { long millisecondsInDay = 24 * 60 * 60 * 1000; long rolledTime = date.getTime() + amount * millisecondsInDay; return new Date(rolledTime); } }