1 /* 2 * Copyright (c) 2015, 2017, 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 import java.lang.reflect.*; 26 import sun.hotspot.WhiteBox; 27 28 /* 29 * Lock the 'value' field of a known shared string, java.lang.Object 30 */ 31 public class LockStringValueTest { 32 public static void main(String args[]) { 33 String s = "LiveOak"; 34 WhiteBox wb = WhiteBox.getWhiteBox(); 35 36 if (wb.areSharedStringsIgnored()) { 37 System.out.println("The shared strings are ignored"); 38 System.out.println("LockStringValueTest: PASS"); 39 return; 40 } 41 42 if (!wb.isShared(s)) { 43 throw new RuntimeException("LockStringValueTest Failed: String is not shared."); 44 } 45 46 Class c = s.getClass(); 47 try { 48 Field f = c.getDeclaredField("value"); 49 f.setAccessible(true); 50 Object v = f.get(s); 51 lock(v); 52 } catch (NoSuchFieldException nfe) { 53 } catch (IllegalAccessException iae) {} 54 } 55 56 public static void lock(Object o) { 57 synchronized (o) { 58 System.out.println("LockStringValueTest: PASS"); 59 } 60 } 61 }