Java tutorial
//package com.java2s; /* CarLogbook. Copyright (C) 2014 Eugene Nadein 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 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.util.Calendar; public class Main { public static void trunkYear(Calendar c) { trunkMonth(c); c.set(Calendar.MONTH, 0); } public static void trunkMonth(Calendar c) { trunkDay(c); c.set(Calendar.DAY_OF_MONTH, 1); } public static void trunkDay(Calendar c) { c.set(Calendar.HOUR, 0); c.set(Calendar.MINUTE, 0); c.set(Calendar.SECOND, 0); } }