1 /*
2 * Copyright (c) 2007, 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 * @test
25 * @bug 4405807
26 * @run main/othervm -Xms10m ReferencesTest
27 * @summary Verify that references from ResourceBundle cache don't prevent
28 * class loader reclamation.
29 */
30
31 import java.io.File;
32 import java.lang.ref.WeakReference;
33 import java.lang.reflect.Field;
34 import java.net.URL;
35 import java.net.URLClassLoader;
36 import java.util.Locale;
37 import java.util.Map;
38 import java.util.MissingResourceException;
39 import java.util.ResourceBundle;
40
41 /**
42 * This test relies on the current behavior of the garbage collector and is
43 * therefore no clear indicator of whether the fix for 4405807 works.
44 * If the test fails, it might indicate a regression, or it might just mean
45 * that a less aggressive garbage collector is used.
46 */
47 public class ReferencesTest {
48
49 private static final int CLASS_LOADER_COUNT = 20;
50
51 // These two parallel arrays have references to the same class loaders.
52 // The weakLoaders array lets us track whether class loaders are being
53 // reclaimed after the references in the loaders array are nulled out.
54 private static ClassLoader[] loaders = new ClassLoader[CLASS_LOADER_COUNT];
55 private static WeakReference[] weakLoaders = new WeakReference[CLASS_LOADER_COUNT];
56
57 public static void main(String[] args) throws Exception {
58
59 URL testDirectory = new File(System.getProperty("test.classes", ".")).toURL();
60
61 for (int i = 0; i < loaders.length; i++) {
62 URL[] urls = { testDirectory };
63 loaders[i] = new URLClassLoader(urls);
64 weakLoaders[i] = new WeakReference(loaders[i]);
65 }
66
67 // fill the ResourceBundle cache with entries for half the class loaders
68 loadBundles(0, CLASS_LOADER_COUNT / 2);
69
70 report("After loading resource bundles for first half of class loaders: ");
71
72 // release the first half of the class loaders
73 for (int i = 0; i < CLASS_LOADER_COUNT / 2; i++) {
74 loaders[i] = null;
75 }
76
77 System.gc();
78
79 report("After releasing first half of class loaders: ");
80
81 // fill the ResourceBundle cache with entries for second half the class loaders
82 loadBundles(CLASS_LOADER_COUNT / 2, CLASS_LOADER_COUNT);
83
84 report("After loading resource bundles for second half of class loaders: ");
85
86 // release the second half of the class loaders
87 for (int i = CLASS_LOADER_COUNT / 2; i < CLASS_LOADER_COUNT; i++) {
88 loaders[i] = null;
89 }
90
91 System.gc();
92
93 report("After releasing second half of class loaders: ");
94
95 // The garbage collector in Tiger actually has reclaimed all class
96 // loaders at this point, but in order not to become too dependent
97 // on the current behavior, we only require that the first half
98 // has been reclaimed.
99 if (countLoaders(0, CLASS_LOADER_COUNT / 2) > 0) {
100 throw new RuntimeException("Too many class loaders not reclaimed yet.");
101 }
102 }
103
104 private static void report(String when) throws Exception {
105 int first = countLoaders(0, CLASS_LOADER_COUNT / 2);
106 int second = countLoaders(CLASS_LOADER_COUNT / 2, CLASS_LOADER_COUNT);
107
108 Class clazz = ResourceBundle.class;
109 Field cacheList = clazz.getDeclaredField("cacheList");
110 cacheList.setAccessible(true);
111 int cacheSize = ((Map)cacheList.get(clazz)).size();
112
113 System.out.println(when);
114 System.out.println(" " + first + " loaders alive in first half");
115 System.out.println(" " + second + " loaders alive in second half");
116 System.out.println(" " + cacheSize + " entries in resource bundle cache");
117 }
118
119 private static void loadBundles(int start, int end) throws Exception {
120 for (int i = start; i < end; i++) {
121 // There's no resource bundle for NonExistantBundle - this
122 // let's us test the case where a resource bundle is not found,
123 // which in the past created a SoftReference on the value side
124 // of the cache.
125 try {
126 ResourceBundle.getBundle("NonExistantBundle", Locale.US, loaders[i]);
127 } catch (MissingResourceException e) {
128 }
129 // There's a base resource bundle for ReferencesTestBundle - the
130 // normal case.
131 ResourceBundle.getBundle("ReferencesTestBundle", Locale.US, loaders[i]);
132 }
133 }
134
135 private static int countLoaders(int start, int end) {
136 int count = 0;
137 for (int i = start; i < end; i++) {
138 if (weakLoaders[i].get() != null) {
139 count++;
140 }
141 }
142 return count;
143 }
144 }