Hello Mark, I think that the issue below was related to the way I was shutting down an instance of ScheduledExecutorService. I changed the way it is shutdown when the context is destroyed...I will update here if I don't receive any more warnings.
However, I now get a warning: WARNING [main] org.apache.tomcat.util.net.AbstractEndpoint.shutdownExecutor The executor associated with thread pool [http-apr-8080] has not fully shutdown. Some application threads may still be running I am not sure if this is related or not? When I do a heap dump with jstack I see http-apr-8080-exec-[1-10] but I don't see any thread named http-apr-8080. Any ideas on how to trouble shoot this? Thanks. On Sun, Jan 31, 2016 at 8:18 PM, Yuval Schwartz <yuval.schwa...@gmail.com> wrote: > > > On Sunday, 31 January 2016, Mark Thomas <ma...@apache.org> wrote: > >> On 31/01/2016 08:06, Yuval Schwartz wrote: >> > Hellow Mark, >> > >> > Thanks for the reply. >> > Follow up questions below. >> > >> > On Fri, Jan 29, 2016 at 6:22 PM, Mark Thomas <ma...@apache.org> wrote: >> > >> >> On 29/01/2016 14:34, Yuval Schwartz wrote: >> >>> Hello, >> >>> >> >>> tomcat version: 8.0.22 >> >>> java: jdk1.8.0_05 >> >>> server: Amazon Linux AMI >> >>> >> >>> I get the following warning message in my catalina log when I >> undeploy a >> >>> web application: >> >>> >> >>> *WARNING [ContainerBackgroundProcessor[StandardEngine[Catalina]]] >> >>> >> org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads >> >> The >> >>> web application [ROOT##002] appears to have started a thread named >> >>> [pool-2-thread-1] but has failed to stop it. This is very likely to >> >> create >> >>> a memory leak. Stack trace of thread* >> >>> >> >>> As you can see, for some reason, I don't get a stack trace of the >> thread. >> >>> Therefore, I have no idea how to debug this warning. >> >>> >> >>> This particular warning was generated when tomcat detected an unused >> >>> version and undeployed it (I set undeployOldVersions="true"). >> >>> >> >>> Does anyone know how I can debug this warning. How can I know more >> about >> >>> this thread? >> >> That looks like a thread from Commons Pool (possibly via DBCP). The >> only >> >> way to be sure you have a leak or not is to use a profiler. See >> >> >> >> >> http://home.apache.org/~markt/presentations/2010-11-04-Memory-Leaks-60mins.pdf >> > >> > >> > Is VisualVM a good profiler to start with considering my system? >> >> Sorry, don't know. Never used it. I use YourKit, mainly because they >> kindly donate free licenses to OpenSource developers to use with their >> OpenSource projects. > > > Thank you Mark, > > I installed VisualVM as a profiler. > I can now see all of the threads that tomcat is "using" (?not sure if > that's the correct term) (there's 35 live threads and 33 daemon threads). > Do you have any recommendations for how I might trouble shoot the original > warning that I got? Would I do a "heap dump"? > I have restarted tomcat since the time of the original warning message, so > I can't expect to find the same thread, correct? > Any tips? > > FYI: I never saw my cpu climbing or anything, I am troubleshooting this > warning solely on seeing the "Warning" message. Is this overkill? Should I > wait until something more severe occurs? (I have not yet gone live with my > webapp but planned on doing so soon). > > Thanks. > > >> >> Mark >> >> > I would just like to confirm that this warning is not something serious. >> > I am currently having a little trouble running VisualVM (jstatd) from a >> > remote machine but can struggle with it a little more to try to get it >> > working. >> > >> > >> > Thanks. >> > >> > >> > >> >> >> >>> I used the manager app and clicked "find leaks" but it said that there >> >> were >> >>> none. >> >>> (Can someone also explain why I have to be cautious when using this >> >> feature >> >>> on production environments). >> >> >> >> It triggers a full GC which may (hopefully briefly) pause the entire >> JVM. >> >> >> >> Mark >> >> >> >> >> >> --------------------------------------------------------------------- >> >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> >> For additional commands, e-mail: users-h...@tomcat.apache.org >> >> >> >> >> > >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> >>
