J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2002 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * @test |
| 26 | * @bug 4684279 |
| 27 | * @summary Empty utility collections should be singletons |
| 28 | * @author Josh Bloch |
| 29 | */ |
| 30 | |
| 31 | import java.util.*; |
| 32 | import java.io.*; |
| 33 | |
| 34 | public class EmptyCollectionSerialization { |
| 35 | private static Object patheticDeepCopy(Object o) throws Exception { |
| 36 | // Serialize |
| 37 | ByteArrayOutputStream bos = new ByteArrayOutputStream(); |
| 38 | ObjectOutputStream oos = new ObjectOutputStream(bos); |
| 39 | oos.writeObject(o); |
| 40 | byte[] serializedForm = bos.toByteArray(); |
| 41 | |
| 42 | // Deserialize |
| 43 | InputStream is = new ByteArrayInputStream(serializedForm); |
| 44 | ObjectInputStream ois = new ObjectInputStream(is); |
| 45 | return ois.readObject(); |
| 46 | } |
| 47 | |
| 48 | private static boolean isSingleton(Object o) throws Exception { |
| 49 | return patheticDeepCopy(o) == o; |
| 50 | } |
| 51 | |
| 52 | public static void main(String[] args) throws Exception { |
| 53 | if (!isSingleton(Collections.EMPTY_SET)) |
| 54 | throw new Exception("EMPTY_SET"); |
| 55 | if (!isSingleton(Collections.EMPTY_LIST)) |
| 56 | throw new Exception("EMPTY_LIST"); |
| 57 | if (!isSingleton(Collections.EMPTY_MAP)) |
| 58 | throw new Exception("EMPTY_MAP"); |
| 59 | } |
| 60 | } |