Here you can find the source of getCalendar()
private static Calendar getCalendar()
//package com.java2s; /*/* w w w . j a v a2 s . c o m*/ Copyright ? 2008 Brent Boyer This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser 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 Lesser GNU General Public License for more details. You should have received a copy of the Lesser GNU General Public License along with this program (see the license directory in this project). If not, see <http://www.gnu.org/licenses/>. */ import java.util.Calendar; public class Main { private static final ThreadLocal<Calendar> calendarPerThread = new ThreadLocal<Calendar>() { protected synchronized Calendar initialValue() { return Calendar.getInstance(); } }; private static Calendar getCalendar() { return calendarPerThread.get(); } }