[WW-4058] ContainerHolder causes ThreadLocal memory leak

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.14
• Fix Version/s: 2.3.15
• Component/s: Core Actions

Environment

Tomcat 7.0.39
java version "1.7.0_15"
OpenJDK Runtime Environment (IcedTea7 2.3.7) (7u15-2.3.7-0ubuntu1~12.04.1)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

• Assignee: Lukasz Lenart
• Reporter: Boris Morris
• Created: 23/Apr/13 11:24
• Updated: 12/Jun/14 14:29
• Resolved: 30/Apr/13 09:24

Description

The localContext ThreadLocal is not cleaned up properly when stopping / undeploying / redeploying a S2 application. This will in most cases cause the web application ClassLoader not to be garbage collected, thus leaving a redeployment memory leak.

I am using Tomcat 7.0.39 and when I undeploy my application the following is reported in the logs:

2013-04-23 12:00:31,082 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,083 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,101 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,101 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,101 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,101 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,102 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,102 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,103 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,103 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,103 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
2013-04-23 12:00:31,103 [request-worker-4] ERROR org.apache.catalina.loader.WebappClassLoader- The web application [/dev] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@7f2283e1]) and a value of type [com.opensymphony.xwork2.inject.ContainerImpl] (value [com.opensymphony.xwork2.inject.ContainerImpl@330069fc]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

After poking around in the heap dump it would seem that Tomcat is correct. There is indeed a GC root at the ThreadLocal used by the ContainerImpl.

Issue Links

• is a clone of: WW-3768 XWork ContainerImpl causes ThreadLocal memory leak
• is duplicated by: WW-4361 Memory Leak Issue