StringConversion.java revision 553:9d9f26857129 
1/*
2 * Copyright (c) 1997, 1998, 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 4030173 4071548
27 * @summary Verify correct conversion of non-string arguments in string concatenation.
28 * @author maddox
29 *
30 * @compile StringConversion.java
31 * @run main StringConversion
32 */
33
34class FooBar {
35    public String toString(){
36        return null;
37    }
38}
39
40public class StringConversion {
41
42    static void check(int testid, String have, String expect)
43                throws Exception {
44        if ((have == null && have != expect) ||
45                (have != null && !have.equals(expect))) {
46            String msg =
47                "TEST " + testid + ": HAVE \"" +
48                have + "\" EXPECT \"" + expect + "\"";
49            System.out.println("StringConversion: " + msg);
50            throw new Exception(msg);
51        }
52    }
53
54    public static void main(String[] args) throws Exception {
55
56        String s;
57        String n = null;
58        Object o = null;
59        FooBar m = new FooBar();
60
61        // Null reference must be converted to "null"
62
63        // Conversion will be done by 'StringBuffer.append'.
64        s = "foo" + n;
65        check(11, s, "foonull");
66        s = n + "bar";
67        check(12, s, "nullbar");
68        s = "foo" + o;
69        check(13, s, "foonull");
70        s = o + "bar";
71        check(14, s, "nullbar");
72
73        // Conversion will be done by 'String.valueOf'.
74        s = "" + n;
75        check(21, s, "null");
76        s = n + "";
77        check(22, s, "null");
78        s = "" + o;
79        check(23, s, "null");
80        s = o + "";
81        check(24, s, "null");
82
83        // Null 'toString' result must be converted to "null"
84
85        // Conversion will be done by 'StringBuffer.append'.
86        s = "foo" + m;
87        check(31, s, "foonull");
88        s = m + "bar";
89        check(32, s, "nullbar");
90
91        // Conversion will be done by 'String.valueOf'.
92        s = "" + m;
93        check(43, s, "null");
94        s = m + "";
95        check(44, s, "null");
96
97        // A character array must be converted as if by
98        // 'toString', i.e., it is treated as an 'Object'.
99
100        s = "polymorph";
101        char[] ca = {'i', 's', 'm'};
102
103        check(51, s + ca, s + ca.toString());
104        check(52, ca + s, ca.toString() + s);
105
106        System.out.println("OK");
107    }
108}
109