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https://issues.apache.org/jira/browse/POOL-411?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17741210#comment-17741210
]
Gary D. Gregory commented on POOL-411:
--------------------------------------
The following allows the test to pass locally for me in Eclipse, running it
over and over:
{noformat}
diff --git
a/src/main/java/org/apache/commons/pool2/impl/GenericKeyedObjectPool.java
b/src/main/java/org/apache/commons/pool2/impl/GenericKeyedObjectPool.java
index 0f8a275..b67cc00 100644
--- a/src/main/java/org/apache/commons/pool2/impl/GenericKeyedObjectPool.java
+++ b/src/main/java/org/apache/commons/pool2/impl/GenericKeyedObjectPool.java
@@ -30,6 +30,7 @@
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.locks.Lock;
@@ -833,13 +834,13 @@
lock.lock();
final ObjectDeque<T> objectDeque = poolMap.get(k);
if (objectDeque != null) {
+ // Potential to remove key
+ // Upgrade to write lock
+ lock.unlock();
+ lock = keyLock.writeLock();
+ lock.lock();
final long numInterested =
objectDeque.getNumInterested().decrementAndGet();
if (numInterested == 0 && objectDeque.getCreateCount().get()
== 0) {
- // Potential to remove key
- // Upgrade to write lock
- lock.unlock();
- lock = keyLock.writeLock();
- lock.lock();
if (objectDeque.getCreateCount().get() == 0 &&
objectDeque.getNumInterested().get() == 0) {
// NOTE: Keys must always be removed from both poolMap
and
// poolKeyList at the same time while protected by
@@ -1385,16 +1386,17 @@
lock.unlock();
lock = keyLock.writeLock();
lock.lock();
- objectDeque = poolMap.get(k);
- if (objectDeque == null) {
- objectDeque = new ObjectDeque<>(fairness);
- objectDeque.getNumInterested().incrementAndGet();
+ final AtomicBoolean allocated = new AtomicBoolean();
+ objectDeque = poolMap.computeIfAbsent(k, key -> {
+ allocated.set(true);
+ final ObjectDeque<T> deque = new ObjectDeque<>(fairness);
+ deque.getNumInterested().incrementAndGet();
// NOTE: Keys must always be added to both poolMap and
// poolKeyList at the same time while protected by
- // keyLock.writeLock()
- poolMap.put(k, objectDeque);
poolKeyList.add(k);
- } else {
+ return deque;
+ });
+ if (!allocated.get()) {
objectDeque.getNumInterested().incrementAndGet();
}
} else {
{noformat}
> NPE when deregistering key at end of borrow
> -------------------------------------------
>
> Key: POOL-411
> URL: https://issues.apache.org/jira/browse/POOL-411
> Project: Commons Pool
> Issue Type: Task
> Affects Versions: 2.11.1
> Reporter: Richard Eckart de Castilho
> Priority: Major
> Fix For: 2.12.0
>
>
> There is a potential for an NPE happening in the finally block of
> borrowObject:
> {noformat}
> Caused by: java.lang.NullPointerException: Cannot invoke
> "org.apache.commons.pool2.impl.GenericKeyedObjectPool$ObjectDeque.getNumInterested()"
> because "objectDeque" is null
> at
> org.apache.commons.pool2.impl.GenericKeyedObjectPool.deregister(GenericKeyedObjectPool.java:821)
> at
> org.apache.commons.pool2.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:507)
> at
> org.apache.commons.pool2.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:350)
>
> {noformat}
> From reading the code, it seems this could happen e.g. if a pool is
> concurrently cleared while a borrow is in progress.
> Not sure what a proper solution here would be. Maybe deregister should
> silently do nothing if poolMap.get(k) returns null?
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