java - Netty causing memory leak in tomcat -

i'm using netty 4.0.26.final along tomcat 8 implement embedded tcp server inside web application.

the problem when stop tomcat i'm getting message :

the web application [app] appears have started thread named   [nioeventloopgroup-2-1] has failed stop it. create memory leak. stack trace of thread:  sun.nio.ch.windowsselectorimpl$subselector.poll0(native method)  sun.nio.ch.windowsselectorimpl$subselector.poll(windowsselectorimpl.java:296)  sun.nio.ch.windowsselectorimpl$subselector.access$400(windowsselectorimpl.java:278)  sun.nio.ch.windowsselectorimpl.doselect(windowsselectorimpl.java:159)  sun.nio.ch.selectorimpl.lockanddoselect(selectorimpl.java:87)  sun.nio.ch.selectorimpl.select(selectorimpl.java:98)  io.netty.channel.nio.nioeventloop.select(nioeventloop.java:622)  io.netty.channel.nio.nioeventloop.run(nioeventloop.java:310)  io.netty.util.concurrent.singlethreadeventexecutor$2.run(singlethreadeventexecutor.java:111)  io.netty.util.concurrent.defaultthreadfactory$defaultrunnabledecorator.run(defaultthreadfactory.java:137) 

i've tried using class shutdown threads before closing tomcat i'm still having same problem.

@component public class myappservletcontextlistener implements servletcontextlistener{      @override     public void contextinitialized(servletcontextevent arg0) {     }       @override     public void contextdestroyed(servletcontextevent arg0) {         trackingdaemon trackingdaemon= (trackingdaemon) applicationcontextprovider.getbean("trackingdaemon");         trackingdaemon.bossgroup.shutdowngracefully();         trackingdaemon.workergroup.shutdowngracefully();     }   } 

bossgroup , workergroup are:

eventloopgroup bossgroup = new nioeventloopgroup();  eventloopgroup workergroup = new nioeventloopgroup(); 

any appreciated..

i have had problem netty 4 , tomcat 7 , solved capturing future event shutdowngracefully() , awaiting completion. method below called when closing down application.

private void stopchannel() {  log.trace("stopping server socket on port '{}'", port);  sendmessageservice.deregistermessagesender(endpointid);  try {    (channel channel : channels) {      if (channel != null) {        channel.close();      }    }    serverchannel.close().sync();    log.trace("server socket on port '{}' stopped.", port);  } catch (interruptedexception e) {     throw new runtimeexception(e);  } {     future<?> fc = connectiongroup.shutdowngracefully();     future<?> fw = workergroup.shutdowngracefully();    try {      fc.await(); // when shutting down in tomcat waits netty threads die      fw.await();    } catch (interruptedexception e) {     throw new runtimeexception(e);   }    log.trace("server workergroup has shutdown on port '{}'", port); } 

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