Java tutorial
//package com.java2s; /* * #%L * Netarchivesuite - common - test * %% * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library, * the National Library of France and the Austrian National Library. * %% * 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 2.1 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 Lesser Public License for more details. * * You should have received a copy of the GNU General Lesser Public * License along with this program. If not, see * <http://www.gnu.org/licenses/lgpl-2.1.html>. * #L% */ public class Main { private static ThreadGroup rootThreadGroup = null; public static ThreadGroup getRootThreadGroup() { if (rootThreadGroup != null) { return rootThreadGroup; } ThreadGroup tg = Thread.currentThread().getThreadGroup(); ThreadGroup ptg; while ((ptg = tg.getParent()) != null) { tg = ptg; } return tg; } }