1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.lang.reflect.Method;
import java.lang.reflect.Field;
/*
* @test
* @summary Unit test for FinalizerHistogram
* @modules java.base/java.lang.ref:open
* @run main FinalizerHistogramTest
*/
public class FinalizerHistogramTest {
static ReentrantLock lock = new ReentrantLock();
static volatile int wasInitialized = 0;
static volatile int wasTrapped = 0;
static final int objectsCount = 1000;
static class MyObject {
public MyObject() {
// Make sure object allocation/deallocation is not optimized out
wasInitialized += 1;
}
protected void finalize() {
// Trap the object in a finalization queue
wasTrapped += 1;
lock.lock();
}
}
public static void main(String[] argvs) {
try {
lock.lock();
for(int i = 0; i < objectsCount; ++i) {
new MyObject();
}
System.out.println("Objects intialized: " + objectsCount);
System.gc();
while(wasTrapped < 1);
Class<?> klass = Class.forName("java.lang.ref.FinalizerHistogram");
Method m = klass.getDeclaredMethod("getFinalizerHistogram");
m.setAccessible(true);
Object entries[] = (Object[]) m.invoke(null);
Class<?> entryKlass = Class.forName("java.lang.ref.FinalizerHistogram$Entry");
Field name = entryKlass.getDeclaredField("className");
name.setAccessible(true);
Field count = entryKlass.getDeclaredField("instanceCount");
count.setAccessible(true);
System.out.println("Unreachable instances waiting for finalization");
System.out.println("#instances class name");
System.out.println("-----------------------");
boolean found = false;
for (Object entry : entries) {
Object e = entryKlass.cast(entry);
System.out.printf("%10d %s\n", count.get(e), name.get(e));
if (((String) name.get(e)).indexOf("MyObject") != -1 ) {
found = true;
}
}
if (!found) {
throw new RuntimeException("MyObject is not found in test output");
}
System.out.println("Test PASSED");
} catch(Exception e) {
System.err.println("Test failed with " + e);
e.printStackTrace(System.err);
throw new RuntimeException("Test failed");
} finally {
lock.unlock();
}
}
}
|
