/* * Copyright (c) 2015, 2017, Oracle and/or its affiliates. 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. * */ import java.lang.reflect.*; import sun.hotspot.WhiteBox; /* * Lock the 'value' field of a known shared string, java.lang.Object */ public class LockStringValueTest { public static void main(String args[]) { String s = "LiveOak"; WhiteBox wb = WhiteBox.getWhiteBox(); if (wb.areSharedStringsIgnored()) { System.out.println("The shared strings are ignored"); System.out.println("LockStringValueTest: PASS"); return; } if (!wb.isShared(s)) { throw new RuntimeException("LockStringValueTest Failed: String is not shared."); } Class c = s.getClass(); try { Field f = c.getDeclaredField("value"); f.setAccessible(true); Object v = f.get(s); lock(v); } catch (NoSuchFieldException nfe) { } catch (IllegalAccessException iae) {} } public static void lock(Object o) { synchronized (o) { System.out.println("LockStringValueTest: PASS"); } } }