[CAUSEWAY-1506] tomcat shutdown - threads in PARK state

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.13.0
• Fix Version/s: 2.0.0-M1
• Component/s: Core
• Assignee: Andi Huber
• Reporter: Timothy Simecsek
• Created: 29/Sep/16 17:04
• Updated: 14/Mar/18 16:49
• Resolved: 03/Mar/18 08:02

Description

Hi Dan,

Today I monitored threads created within our application while running on tomcat 8.5.3x64 because of an issue in my code.

While doing that I noticed that there were two threads called Thread-7 and Thread-8 (name was stable during a lot of starts but only on the first start) that I wasn't able to find in my code so I debugged a bit deeper and found that they were created in org.apache.isis.core.runtime.threadpool.ThreadPoolSupport:76 during start-up.

After that they are going to state PARK and reside even when undeploying the application from tomcat.

I haven't looked much at your code but I believe you should call shutdown on the ThreadPoolExecutor that you are using once you are finished or in PreDestroy situation. At least I had a very similar issue in my application and shutdown() solved it.

Please find attached a screenshot of IntelliJ view during debug, the screenshot of VisualVM and the catalina log from tomcat complaining about these two threads.

Issue Links

• relates to: CAUSEWAY-862 Warnings for memory leaks when quitting Tomcat