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[LOGGING-119] Prevent potential deadlock in WeakHashtable.

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git-svn-id: https://svn.apache.org/repos/asf/commons/proper/logging/trunk@1435077 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart
2013-01-18 10:51:35 +00:00
parent 5c81b031c3
commit ae4698230a
3 changed files with 19 additions and 5 deletions
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3
src/changes/changes.xml
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@@ -44,6 +44,9 @@ The <action> type attribute can be add,update,fix,remove.
</properties>
<body>
<release version="1.1.2" date="In SVN" description="Bug fixes.">
<action type="fix" issue="LOGGING-119">
Prevent potential deadlock scenario in WeakHashtable.
</action>
<action type="fix" issue="LOGGING-130">
Potential missing privileged block for class loader.
</action>

17
src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
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@@ -19,11 +19,13 @@ package org.apache.commons.logging.impl;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
@@ -217,7 +219,7 @@ public final class WeakHashtable extends Hashtable {
/**
*@see Hashtable
*/
public Object put(Object key, Object value) {
public synchronized Object put(Object key, Object value) {
// check for nulls, ensuring semantics match superclass
if (key == null) {
throw new NullPointerException("Null keys are not allowed");
@@ -265,7 +267,7 @@ public final class WeakHashtable extends Hashtable {
/**
*@see Hashtable
*/
public Object remove(Object key) {
public synchronized Object remove(Object key) {
// for performance reasons, only purge every
// MAX_CHANGES_BEFORE_PURGE times
if (changeCount++ > MAX_CHANGES_BEFORE_PURGE) {
@@ -317,12 +319,21 @@ public final class WeakHashtable extends Hashtable {
* have been garbage collected.
*/
private void purge() {
final List toRemove = new ArrayList();
synchronized (queue) {
WeakKey key;
while ((key = (WeakKey) queue.poll()) != null) {
super.remove(key.getReferenced());
toRemove.add(key.getReferenced());
}
}
// LOGGING-119: do the actual removal of the keys outside the sync block
// to prevent deadlock scenarios as purge() may be called from
// non-synchronized methods too
final int size = toRemove.size();
for (int i = 0; i < size; i++) {
super.remove(toRemove.get(i));
}
}
/**

4
src/test/java/org/apache/commons/logging/impl/WeakHashtableTest.java → src/test/java/org/apache/commons/logging/impl/WeakHashtableTestCase.java
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@@ -30,7 +30,7 @@ import java.util.Set;
import junit.framework.TestCase;
public class WeakHashtableTest extends TestCase {
public class WeakHashtableTestCase extends TestCase {
private static final int WAIT_FOR_THREAD_COMPLETION = 5000; // 5 seconds
private static final int RUN_LOOPS = 3000;
@@ -50,7 +50,7 @@ public class WeakHashtableTest extends TestCase {
private Long valueTwo;
private Long valueThree;
public WeakHashtableTest(String testName) {
public WeakHashtableTestCase(String testName) {
super(testName);
}