/* * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2021, BELLSOFT. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* * LoadLibraryDeadlock class triggers the deadlock between the two * lock objects - ZipFile object and ClassLoader.loadedLibraryNames hashmap. * Thread #2 loads a signed jar which leads to acquiring the lock objects in * natural order (ZipFile then HashMap) - loading a signed jar may involve * Providers initialization. Providers may load native libraries. * Thread #1 acquires the locks in reverse order, first entering loadLibrary * called from Class1, then acquiring ZipFile during the search for a class * triggered from JNI. */ import java.lang.*; import java.net.URISyntaxException; public class LoadLibraryDeadlock { public static void main(String[] args) { System.out.println("LoadLibraryDeadlock test started"); Thread t1 = new Thread() { public void run() { try { // an instance of unsigned class that loads a native library Class c1 = Class.forName("Class1"); Object o = c1.newInstance(); System.out.println("Class1 loaded from " + getLocation(c1)); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) { System.out.println("Class Class1 not found."); throw new RuntimeException(e); } } }; Thread t2 = new Thread() { public void run() { try { // load a class from a signed jar, which locks the JarFile Class c2 = Class.forName("p.Class2"); System.out.println("Class2 loaded from " + getLocation(c2)); } catch (ClassNotFoundException e) { System.out.println("Class Class2 not found."); throw new RuntimeException(e); } } }; t2.start(); t1.start(); try { t1.join(); t2.join(); } catch (InterruptedException ex) { throw new RuntimeException(ex); } } private static String getLocation(Class c) { var pd = c.getProtectionDomain(); var cs = pd != null ? pd.getCodeSource() : null; try { // same format as returned by TestLoadLibraryDeadlock::getLocation return cs != null ? cs.getLocation().toURI().getPath() : null; } catch (URISyntaxException ex) { throw new RuntimeException(ex); } } }