Perm or Metaspace OOME due to classloaders persisted by MultiThreadedHttpConnectionManager$ReferenceQueueThreads

Environment

• JBoss Enterprise Application Platform (EAP)

Issue

• We hit an OOME after several redeploys and a heap dump shows application classloaders are persisted by org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$ReferenceQueueThreads.

Resolution

• The application needs to call org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.shutdownAll() upon undeployment to stop those threads and ensure proper clean up. That could be done in an application lifecycle listener as described in Application lifecycle listeners in EAP 6

Root Cause

• The application is starting but not stopping MultiThreadedHttpConnectionManager$ReferenceQueueThreads.

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