1 /* 2 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 4994705 27 * 28 * @summary deadlock in LogManager 29 * @author Serguei Spitsyn / SAP 30 * 31 * @build LoggingDeadlock 32 * @run main/timeout=15 LoggingDeadlock 33 * 34 * There can be a deadlock between two class initializations. 35 * It happens if the LogManager.<clinit> and the Logger.<clinit> 36 * are invoked concurrently on two different threads. 37 * There is a cyclic dependence between the two static initializers: 38 * 1. LogManager.<clinit> instantiate the class RootLogger which 39 * is a subclass of the Logger class. 40 * It requires the Logger class initialization to complete. 41 * 2. Logger.<clinit> initializes the field "global", so it 42 * it makes a call: Logger.getLogger("global"). 43 * Subsequently the LogManager static method getLogManager() 44 * is called which requires the LogManager class 45 * initialization to complete. 46 * This cyclic dependence causes a deadlock, so two class 47 * initializations are waiting for each other. 48 * This is a regression test for this bug. 49 */ 50 51 52 import java.util.logging.LogManager; 53 import java.util.logging.Logger; 54 55 public class LoggingDeadlock { 56 57 public static void randomDelay() { 58 int runs = (int) Math.random() * 1000000; 59 int c = 0; 60 61 for (int i = 0; i < runs; ++i) { 62 c = c + i; 63 } 64 } 65 66 public static void main(String[] args) throws InterruptedException{ 67 Thread t1 = new Thread(new Runnable() { 68 public void run() { 69 randomDelay(); 70 // Trigger Logger.<clinit> 71 Logger.getAnonymousLogger(); 72 } 73 }); 74 75 Thread t2 = new Thread(new Runnable() { 76 public void run() { 77 randomDelay(); 78 // Trigger LogManager.<clinit> 79 LogManager.getLogManager(); 80 } 81 }); 82 83 t1.start(); 84 t2.start(); 85 86 t1.join(); 87 t2.join(); 88 System.out.println("\nTest passed"); 89 } 90 }