1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 import java.util.Random; 18 19 public class Main { 20 private static final int buckets = 16 * 1024; 21 private static final int bufferSize = 1024; 22 23 static class ByteContainer { 24 public byte[] bytes; 25 } 26 main(String[] args)27 public static void main(String[] args) throws Exception { 28 ByteContainer[] l = new ByteContainer[buckets]; 29 30 for (int i = 0; i < buckets; ++i) { 31 l[i] = new ByteContainer(); 32 } 33 34 Random rnd = new Random(123456); 35 for (int i = 0; i < buckets / 256; ++i) { 36 int index = rnd.nextInt(buckets); 37 l[index].bytes = new byte[bufferSize]; 38 39 // Try to get GC to run if we can 40 Runtime.getRuntime().gc(); 41 42 // Shuffle the array to try cause the lost object problem: 43 // This problem occurs when an object is white, it may be 44 // only referenced from a white or grey object. If the white 45 // object is moved during a CMS to be a black object's field, it 46 // causes the moved object to not get marked. This can result in 47 // heap corruption. A typical way to address this issue is by 48 // having a card table. 49 // This aspect of the test is meant to ensure that card 50 // dirtying works and that we check the marked cards after 51 // marking. 52 // If these operations are not done, a segfault / failed assert 53 // should occur. 54 for (int j = 0; j < l.length; ++j) { 55 int a = l.length - i - 1; 56 int b = rnd.nextInt(a); 57 byte[] temp = l[a].bytes; 58 l[a].bytes = l[b].bytes; 59 l[b].bytes = temp; 60 } 61 } 62 System.out.println("Test complete"); 63 } 64 } 65