CODEWITHSUNDEEP
javamultithreadingtomcatoperating-system
Vasanth Nag K V
Vasanth Nag K V

Reputation: 4988

Thread starts and fails to stops with Tomcat. What's happening?

i have a java multi-threaded program that is running. i am running it on a tomcat server. when the threads are still running, some executing tasks, some still waiting for some thing to return and all kinds of things, assume i stop the server all of a sudden in this scenario.. when i do i get a warning on the tomcat terminal saying a thread named x is still running and the server is being stopped so this might lead to a memory leakage. what is the OS actually trying to tell me here? can someone help me understand this?? i am running this program on my system several times and i have stopped the server abruptly 3 times and i have seen this message when ever i do that. have i runined my server? (i mean my system). did i do something very dangerous????

please help.

Thanks in advance!

Upvotes: 2

Views: 892

Answers (2)

Gray
Gray

Reputation: 116938

when i do i get a warning on the tomcat terminal saying a thread named x is still running and the server is being stopped so this might lead to a memory leakage. what is the OS actually trying to tell me here?

Tomcat (not the OS) is surmising from this extra thread that some part of your code forked a thread that may not be properly cleaning itself up. It is thinking that maybe this thread is forked more than once and if your process runs for a long time, it could fill up usable memory which would cause the JVM to lock up or at least get very slow.

have i ruined my server? (i mean my system). did i do something very dangerous????

No, no. This is about the tomcat process itself. It is worried that this memory leak may stop its ability to do its job as software -- nothing more. Unless you see more than one thread or until you see memory problems with your server (use jconsole for this) then I would only take it as a warning and a caution.

Upvotes: 1

merlin2011
merlin2011

Reputation: 75649

It sounds like your web server is forking processes which are not terminated when you stop the server. Those could lead to a memory leak because they represent processes that will never die unless you reboot or manually terminate them with the kill command.

I doubt that you will permanently damage your system, unless those orphaned processes are doing something bad, but that would be unrelated to you stopping the server. You should probably do something like ps aux | grep tomcat to find the leftover processes and do the following

  1. Kill them so they don't take up more system resoures.
  2. Figure out why they are persisting when the server is stopped. This sounds like a misbehaving server.

Upvotes: 0

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