1 /*
2 * Copyright (c) 1999, 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 4190323
27 * @summary EMPTY_SET, EMPTY_LIST, and the collections returned by
28 * nCopies and singleton were spec'd to be serializable, but weren't.
29 * @library /test/lib
30 */
31
32 import jdk.test.lib.valueclass.AsValueClass;
33 import java.io.ByteArrayInputStream;
34 import java.io.ByteArrayOutputStream;
35 import java.io.ObjectInputStream;
36 import java.io.ObjectOutputStream;
37 import java.io.Serializable;
38 import java.util.Collections;
39 import java.util.List;
40 import java.util.Set;
41
42 public class Ser {
43
44 @AsValueClass
45 static final class SerV implements Serializable {
46 int x;
47 SerV(int x) { this.x = x; }
48 public boolean equals(Object o) { return o instanceof SerV v && x == v.x; }
49 public int hashCode() { return x; }
50 private Object writeReplace() { return new SerProxy(x); }
51 private static class SerProxy implements Serializable {
52 int x;
53 SerProxy(int x) { this.x = x; }
54 private Object readResolve() { return new SerV(x); }
55 }
56 }
57
58 public static void main(String[] args) throws Exception {
59
60 try {
61 ByteArrayOutputStream bos = new ByteArrayOutputStream();
62 ObjectOutputStream out = new ObjectOutputStream(bos);
63 out.writeObject(Collections.EMPTY_SET);
64 out.flush();
65 ObjectInputStream in = new ObjectInputStream(
66 new ByteArrayInputStream(bos.toByteArray()));
67
68 if (!Collections.EMPTY_SET.equals(in.readObject()))
69 throw new RuntimeException("empty set Ser/Deser failure.");
70 } catch (Exception e) {
71 throw new RuntimeException("Failed to serialize empty set:" + e);
72 }
73
74 try {
75 ByteArrayOutputStream bos = new ByteArrayOutputStream();
76 ObjectOutputStream out = new ObjectOutputStream(bos);
77 out.writeObject(Collections.EMPTY_LIST);
78 out.flush();
79 ObjectInputStream in = new ObjectInputStream(
80 new ByteArrayInputStream(bos.toByteArray()));
81
82 if (!Collections.EMPTY_LIST.equals(in.readObject()))
83 throw new RuntimeException("empty list Ser/Deser failure.");
84 } catch (Exception e) {
85 throw new RuntimeException("Failed to serialize empty list:" + e);
86 }
87
88 try {
89 ByteArrayOutputStream bos = new ByteArrayOutputStream();
90 ObjectOutputStream out = new ObjectOutputStream(bos);
91 Set gumby = Collections.singleton("gumby");
92 out.writeObject(gumby);
93 out.flush();
94 ObjectInputStream in = new ObjectInputStream(
95 new ByteArrayInputStream(bos.toByteArray()));
96
97 if (!gumby.equals(in.readObject()))
98 throw new RuntimeException("Singleton Ser/Deser failure.");
99 } catch (Exception e) {
100 throw new RuntimeException("Failed to serialize singleton:" + e);
101 }
102
103 try {
104 ByteArrayOutputStream bos = new ByteArrayOutputStream();
105 ObjectOutputStream out = new ObjectOutputStream(bos);
106 List gumbies = Collections.nCopies(50, "gumby");
107 out.writeObject(gumbies);
108 out.flush();
109 ObjectInputStream in = new ObjectInputStream(
110 new ByteArrayInputStream(bos.toByteArray()));
111
112 if (!gumbies.equals(in.readObject()))
113 throw new RuntimeException("nCopies Ser/Deser failure.");
114 } catch (Exception e) {
115 throw new RuntimeException("Failed to serialize nCopies:" + e);
116 }
117
118 try {
119 ByteArrayOutputStream bos = new ByteArrayOutputStream();
120 ObjectOutputStream out = new ObjectOutputStream(bos);
121 Set<SerV> one = Collections.singleton(new SerV(1));
122 out.writeObject(one);
123 out.flush();
124 ObjectInputStream in = new ObjectInputStream(
125 new ByteArrayInputStream(bos.toByteArray()));
126 if (!one.equals(in.readObject()))
127 throw new RuntimeException("value singleton Ser/Deser failure");
128 } catch (Exception e) {
129 throw new RuntimeException("Failed to serialize value singleton: " + e);
130 }
131
132 try {
133 ByteArrayOutputStream bos = new ByteArrayOutputStream();
134 ObjectOutputStream out = new ObjectOutputStream(bos);
135 List<SerV> many = Collections.nCopies(5, new SerV(2));
136 out.writeObject(many);
137 out.flush();
138 ObjectInputStream in = new ObjectInputStream(
139 new ByteArrayInputStream(bos.toByteArray()));
140 if (!many.equals(in.readObject()))
141 throw new RuntimeException("value nCopies Ser/Deser failure");
142 } catch (Exception e) {
143 throw new RuntimeException("Failed to serialize value nCopies: " + e);
144 }
145 }
146 }