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/*
* 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.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea and Martin Buchholz with assistance from
* members of JCP JSR-166 Expert Group and released to the public
* domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* @test
* @bug 6236036 6264015
* @modules java.base/java.util.concurrent:open
* java.base/java.util.concurrent.locks:open
* @summary Checks for a memory leak when a sequence of aborted timed
* waits occur without a signal. Uses the strategy of detecting
* changes in the size of the object graph retained by a root object.
*/
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.TimeUnit;
public class PollMemoryLeak {
public static void main(String[] args) throws Throwable {
new PollMemoryLeak().main();
}
void main() throws Throwable {
test(new LinkedBlockingDeque(10));
test(new LinkedBlockingQueue(10));
test(new LinkedTransferQueue());
test(new ArrayBlockingQueue(10));
test(new PriorityBlockingQueue());
test(new SynchronousQueue());
test(new SynchronousQueue(true));
}
void test(BlockingQueue q) throws Throwable {
assertNoLeak(q, () -> timedPoll(q));
// A demo that the leak detection infrastructure works
// assertNoLeak(q, () -> q.add(1));
// printRetainedObjects(q);
}
static void timedPoll(BlockingQueue q) {
try { q.poll(1, TimeUnit.NANOSECONDS); }
catch (InterruptedException ex) { throw new AssertionError(ex); }
}
// -------- leak detection infrastructure ---------------
void assertNoLeak(Object root, Runnable r) {
int prev = retainedObjects(root).size();
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) r.run();
int next = retainedObjects(root).size();
if (next <= prev)
return;
prev = next;
}
throw new AssertionError(
String.format("probable memory leak in %s: %s",
root.getClass().getSimpleName(), root));
}
ConcurrentHashMap<Class<?>, Collection<Field>> classFields
= new ConcurrentHashMap<>();
Collection<Field> referenceFieldsOf(Class<?> k) {
Collection<Field> fields = classFields.get(k);
if (fields == null) {
fields = new ArrayDeque<Field>();
ArrayDeque<Field> allFields = new ArrayDeque<>();
for (Class<?> c = k; c != null; c = c.getSuperclass())
for (Field field : c.getDeclaredFields())
if (!Modifier.isStatic(field.getModifiers())
&& !field.getType().isPrimitive())
fields.add(field);
AccessibleObject.setAccessible(
fields.toArray(new AccessibleObject[0]), true);
classFields.put(k, fields);
}
return fields;
}
static Object get(Field field, Object x) {
try { return field.get(x); }
catch (IllegalAccessException ex) { throw new AssertionError(ex); }
}
Set<Object> retainedObjects(Object x) {
ArrayDeque<Object> todo = new ArrayDeque<>() {
public void push(Object x) { if (x != null) super.push(x); }};
Set<Object> uniqueObjects = Collections.newSetFromMap(
new IdentityHashMap<Object, Boolean>());
todo.push(x);
while (!todo.isEmpty()) {
Object y = todo.pop();
if (uniqueObjects.contains(y))
continue;
uniqueObjects.add(y);
Class<?> k = y.getClass();
if (k.isArray() && !k.getComponentType().isPrimitive()) {
for (int i = 0, len = Array.getLength(y); i < len; i++)
todo.push(Array.get(y, i));
} else {
for (Field field : referenceFieldsOf(k))
todo.push(get(field, y));
}
}
return uniqueObjects;
}
/** for debugging the retained object graph */
void printRetainedObjects(Object x) {
for (Object y : retainedObjects(x))
System.out.printf("%s : %s%n", y.getClass().getSimpleName(), y);
}
}
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