1 /*
2 * Copyright (c) 2002, 2026, 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 * @test
26 * @bug 4593209 8001667
27 * @summary Reverse comparator was subtly broken
28 * @author Josh Bloch
29 * @library /test/lib
30 */
31
32 import jdk.test.lib.valueclass.VClass;
33 import java.io.ByteArrayInputStream;
34 import java.io.ByteArrayOutputStream;
35 import java.io.ObjectInputStream;
36 import java.io.ObjectOutputStream;
37 import java.util.Arrays;
38 import java.util.Collections;
39 import java.util.Comparator;
40 import java.util.List;
41
42 public class ReverseOrder {
43
44 static byte[] serialBytes(Object o) {
45 try {
46 ByteArrayOutputStream bos = new ByteArrayOutputStream();
47 ObjectOutputStream oos = new ObjectOutputStream(bos);
48 oos.writeObject(o);
49 oos.flush();
50 oos.close();
51 return bos.toByteArray();
52 } catch (Throwable t) {
53 throw new Error(t);
54 }
55 }
56
57 @SuppressWarnings("unchecked")
58 static <T> T serialClone(T o) {
59 try {
60 ObjectInputStream ois = new ObjectInputStream
61 (new ByteArrayInputStream(serialBytes(o)));
62 T clone = (T) ois.readObject();
63 return clone;
64 } catch (Throwable t) {
65 throw new Error(t);
66 }
67 }
68
69 public static void main(String[] args) throws Exception {
70 Foo[] a = { new Foo(2), new Foo(3), new Foo(1) };
71 List list = Arrays.asList(a);
72 Comparator cmp = Collections.reverseOrder();
73 Collections.sort(list, cmp);
74
75 Foo[] golden = { new Foo(3), new Foo(2), new Foo(1) };
76 List goldenList = Arrays.asList(golden);
77 if (!list.equals(goldenList))
78 throw new Exception(list.toString());
79
80 Comparator clone = serialClone(cmp);
81 List list2 = Arrays.asList(a);
82 Collections.sort(list2, clone);
83 if (!list2.equals(goldenList))
84 throw new Exception(list.toString());
85
86 List<VClass> vl = Arrays.asList(new VClass(1, new int[] { 1 }), new VClass(3, new int[] { 3 }), new VClass(2, new int[] { 2 }));
87 Collections.sort(vl, Collections.reverseOrder());
88 if (!vl.equals(Arrays.asList(new VClass(3, new int[] { 3 }), new VClass(2, new int[] { 2 }), new VClass(1, new int[] { 1 }))))
89 throw new RuntimeException("value reverseOrder failed");
90 }
91 }
92
93 class Foo implements Comparable {
94 int val;
95 Foo(int i) { val = i; }
96
97 public int compareTo(Object o) {
98 Foo f = (Foo)o;
99 return (val < f.val ? Integer.MIN_VALUE : (val == f.val ? 0 : 1));
100 }
101
102 public boolean equals(Object o) {
103 return o instanceof Foo && ((Foo)o).val == val;
104 }
105
106 public int hashCode() { return val; }
107
108 public String toString() { return Integer.toString(val); }
109 }