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 
34 class FooBar {
toString()35     public String toString(){
36         return null;
37     }
38 }
39 
40 public class StringConversion {
41 
check(int testid, String have, String expect)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 
main(String[] args)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