1 /* 2 * Copyright (c) 2014, 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 import java.io.ByteArrayInputStream; 25 import java.io.ByteArrayOutputStream; 26 import java.io.ObjectInputStream; 27 import java.io.ObjectOutputStream; 28 import java.lang.reflect.Field; 29 import java.util.Hashtable; 30 31 /** 32 * @test 33 * @bug 8068427 34 * @summary Hashtable deserialization reconstitutes table with wrong capacity 35 */ 36 public class DeserializedLength { 37 38 static boolean testDeserializedLength(int elements) throws Exception { 39 // construct Hashtable 40 float loadFactor = 0.75f; 41 Hashtable<Integer, Integer> ht1 = new Hashtable<>( 42 (int) (elements / loadFactor) + 1, 43 loadFactor 44 ); 45 for (int i = 0; i < elements; i++) { 46 ht1.put(i, i); 47 } 48 49 // serialize it to byte[] array 50 byte[] bytes; 51 try (ByteArrayOutputStream baos = new ByteArrayOutputStream(); 52 ObjectOutputStream oos = new ObjectOutputStream(baos)) { 53 oos.writeObject(ht1); 54 oos.flush(); 55 bytes = baos.toByteArray(); 56 } 57 58 // de-serialize it from byte[] array 59 Hashtable<?, ?> ht2; 60 try (ByteArrayInputStream bais = new ByteArrayInputStream(bytes); 61 ObjectInputStream ois = new ObjectInputStream(bais)) { 62 ht2 = (Hashtable<?, ?>) ois.readObject(); 63 } 64 65 // compare lengths of internal tables 66 Object[] table1 = (Object[]) hashtableTableField.get(ht1); 67 Object[] table2 = (Object[]) hashtableTableField.get(ht2); 68 69 System.out.println("Serialized Hashtable of size=" + ht1.size() + 70 " has internal table.length=" + table1.length + 71 " de-serialized table.length=" + table2.length); 72 73 return table2.length >= table1.length; 74 } 75 76 private static final Field hashtableTableField; 77 78 static { 79 try { 80 hashtableTableField = Hashtable.class.getDeclaredField("table"); 81 hashtableTableField.setAccessible(true); 82 } catch (NoSuchFieldException e) { 83 throw new Error(e); 84 } 85 } 86 87 public static void main(String[] args) throws Exception { 88 boolean ok = true; 89 ok &= testDeserializedLength(10); 90 ok &= testDeserializedLength(50); 91 ok &= testDeserializedLength(500); 92 ok &= testDeserializedLength(5000); 93 if (!ok) { 94 throw new AssertionError("Test failed."); 95 } 96 } 97 }