1 /* 2 * Copyright (c) 2012, 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 package sun.hotspot; 26 import java.security.BasicPermission; 27 28 public class WhiteBox { 29 30 @SuppressWarnings("serial") 31 public static class WhiteBoxPermission extends BasicPermission { 32 public WhiteBoxPermission(String s) { 33 super(s); 34 } 35 } 36 37 private WhiteBox() {} 38 private static final WhiteBox instance = new WhiteBox(); 39 private static native void registerNatives(); 40 41 /** 42 * Returns the singleton WhiteBox instance. 43 * 44 * The returned WhiteBox object should be carefully guarded 45 * by the caller, since it can be used to read and write data 46 * at arbitrary memory addresses. It must never be passed to 47 * untrusted code. 48 */ 49 public synchronized static WhiteBox getWhiteBox() { 50 SecurityManager sm = System.getSecurityManager(); 51 if (sm != null) { 52 sm.checkPermission(new WhiteBoxPermission("getInstance")); 53 } 54 return instance; 55 } 56 57 static { 58 registerNatives(); 59 } 60 61 // Memory 62 public native long getObjectAddress(Object o); 63 public native int getHeapOopSize(); 64 65 // G1 66 public native boolean g1InConcurrentMark(); 67 public native boolean g1IsHumongous(Object o); 68 public native long g1NumFreeRegions(); 69 public native int g1RegionSize(); 70 }