[HTTPCLIENT-841] potential memory leak when using ThreadSafeClientConnManager

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0 Beta 2
• Fix Version/s: 4.0 Final
• Component/s: HttpClient (classic)
• Environment: Leopard 10.5.6, Java 1.5.0_16, Jetty 6.1.7
• Assignee: Unassigned
• Reporter: Ted Slusser
• Created: 15/Apr/09 17:43
• Updated: 25/Jan/11 10:59
• Resolved: 13/Jun/09 10:21

Description

When using ThreadSafeClientConnManager and developing with Jetty using auto-redeploy feature eventually I run into a PermGen out of memory exception. I investigated with YourKit 8.0.6 and found a class loader circular reference in RefQueueWorker. Not really sure what I was doing I made the refQueueHandler non-final and nulled it in the shutdown method of RedQueueWorker. I don't seem to have the problem any longer with circular class loader references.

Here is a diff from 4.0-beta2

— httpclient/src/main/java/org/apache/http/impl/conn/tsccm/RefQueueWorker.jav(revision 763223)
+++ httpclient/src/main/java/org/apache/http/impl/conn/tsccm/RefQueueWorker.jav(working copy)
@@ -50,7 +50,7 @@
protected final ReferenceQueue<?> refQueue;

/** The handler for the references found. */

• protected final RefQueueHandler refHandler;
  + protected RefQueueHandler refHandler;

/**
@@ -112,6 +112,8 @@
this.workerThread = null; // indicate shutdown
wt.interrupt();
}
+
+ refHandler = null;
}