1/*
2 * Copyright (c) 2001, 2005, 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 4421469 6282555
27 * @summary Hashtable's toString method should detect self-referential
28 *          hash tables rather than throwing a StackOverflowException.
29 * @author Josh Bloch, Martin Buchholz
30 */
31
32import java.util.*;
33import java.util.concurrent.*;
34
35public class SelfRef {
36    public static void main(String[] args) {
37        testMap(new Hashtable<Object,Object>());
38        testMap(new HashMap<Object,Object>());
39        testMap(new LinkedHashMap<Object,Object>());
40        testMap(new ConcurrentHashMap<Object,Object>());
41    }
42
43    private static void testMap(Map<Object,Object> m) {
44        if (! (m.toString().equals("{}")))
45            throw new Error();
46        m.put("Harvey", m);
47        if (! (m.toString().equals("{Harvey=(this Map)}")))
48            throw new Error();
49        m.clear();
50        m.put(m, "Harvey");
51        if (! (m.toString().equals("{(this Map)=Harvey}")))
52            throw new Error();
53        m.clear();
54        m.hashCode();
55    }
56}
57