# Tomcat and SEVERE messages in the output **URL:** https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284 **Category:** Elasticsearch **Created:** [April 24, 2011, 7:01pm UTC](https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284 "2011-04-24T19:01:40Z") **Posts on this page:** 4 **Page:** 1
### Author: ![Enrique\_Medina\_Monte](https://avatars.discourse-cdn.com/v4/letter/e/4491bb/32.png) [@Enrique\_Medina\_Monte](https://discuss.elastic.co/u/Enrique_Medina_Monte) #### Post date: [April 24, 2011, 7:01pm UTC](https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284/1 "2011-04-24T19:01:40Z")
Hi, I'm trying to pinpoint some issues I have with my current environment, and found a bunch of this messages in the Tomcat console output: Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@3a3396c1]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.Unicode$2@72ab5b9c]) and a value of type [org.elasticsearch.common.thread.ThreadLocals.Clean ableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@10ee76c1]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) and a value of type [j ava.util.ArrayList] (value [[]]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) and a value of type [org.elasticsearch.comm on.thread.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17b68196]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@4ef5ab03]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@33d3a0bf]) and a value of type [org.springframework.security.context.SecurityC ontextImpl] (value [org.springframework.security.context.SecurityContextImpl@ffffffff: Null authentication]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.Unicode$2@72ab5b9c]) and a value of type [org.elasticsearch.common.thread.ThreadLocals.Clean ableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@62ae7a74]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) and a value of type [j ava.util.ArrayList] (value [[]]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) and a value of type [org.elasticsearch.comm on.thread.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@2ce98849]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [] created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17f287a8]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. I know that ES has nothing to be with Tomcat, but indeed my web application which uses ES is deployed in Tomcat, so I was wondering if anyone has a clue on whether I should just ignore these messages or pay them some attention, and how to proceed. Thanks. ---
### Author: ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy) #### Post date: [April 24, 2011, 7:39pm UTC](https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284/2 "2011-04-24T19:39:22Z")
Most of those are not related to elasticsearch, but of those that are, are you closing the Node / Client you are starting? On Sunday, April 24, 2011 at 10:01 PM, Enrique Medina Montenegro wrote: > Hi, > > I'm trying to pinpoint some issues I have with my current environment, and found a bunch of this messages in the Tomcat console output: > > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t > ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t > ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre > ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@3a3396c1]) but failed to remove it when the web application was stopped. This is very likely to create > a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.Unicode$2@72ab5b9c]) and a value of type [org.elasticsearch.common.thread.ThreadLocals.Clean > ableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@10ee76c1]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) and a value of type [j > ava.util.ArrayList] (value []) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) and a value of type [org.elasticsearch.comm > on.thread.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17b68196]) but failed to remove it when the web application was stopped. This is very likely to > create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t > ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t > ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre > ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@4ef5ab03]) but failed to remove it when the web application was stopped. This is very likely to create > a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@33d3a0bf]) and a value of type [org.springframework.security.context.SecurityC > ontextImpl] (value [org.springframework.security.context.SecurityContextImpl@ffffffff: Null authentication]) but failed to remove it when the web application was stopped. This is very likely to create a > memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.Unicode$2@72ab5b9c]) and a value of type [org.elasticsearch.common.thread.ThreadLocals.Clean > ableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@62ae7a74]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) and a value of type [j > ava.util.ArrayList] (value []) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) and a value of type [org.elasticsearch.comm > on.thread.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@2ce98849]) but failed to remove it when the web application was stopped. This is very likely to > create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) and a value of t > ype [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) and a value of t > ype [java.lang.Integer] (value [0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. > Apr 24, 2011 8:35:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap > SEVERE: The web application created a ThreadLocal with key of type [null] (value [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) and a value of type [org.elasticsearch.common.thre > ad.ThreadLocals.CleanableValue] (value [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17f287a8]) but failed to remove it when the web application was stopped. This is very likely to create > a memory leak. > > I know that ES has nothing to be with Tomcat, but indeed my web application which uses ES is deployed in Tomcat, so I was wondering if anyone has a clue on whether I should just ignore these messages or pay them some attention, and how to proceed. > > Thanks. ---
### Author: ![Barsk](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/barsk/32/13734_2.png) [@Barsk](https://discuss.elastic.co/u/Barsk) #### Post date: [April 26, 2011, 3:38pm UTC](https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284/3 "2011-04-26T15:38:25Z")
``` Hi, Just as a hint about how to (possibly) catch the cause of this. I too use Tomcat but have no such issues. I use NodeClient as my client type and in one of the webapps that is a standard servlet based app I create the node instance in the servlet init() method, and remove it in the destroy() method. These are the standard servlet lifecycle methods called on init and destroy of the servlet. In my other webapp that is Spring based I use the Spring beans configuration like this: <bean id="esManager" class="se.devo.bertmarks.service.impl.ElasticSearchManagerImpl"        init-method="init"    destroy-method="destroy">        <property name="clusterName" value="${es.clusterName}"/>        <property name="index" value="${es.index}"/>        <property name="type" value="${es.type}"/>  </bean> The init-method and destroy-methods are called when the spring bean is created and destroyed. In my case these are called simply init() and destroy() just as in the servlet variant. /Kristian     Shay Banon skrev 2011-04-24 21:39:
Most of those are not related to elasticsearch, but of those that are, are you closing the Node / Client you are starting? ``` On Sunday, April 24, 2011 at 10:01 PM, Enrique Medina Montenegro wrote: > Hi, > > I'm trying to pinpoint some issues I have with my > current environment, and found a bunch of this > messages in the Tomcat console output: > > Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) > and a value of type [java.lang.Boolean] (value [false]) but > failed to remove it when the web application was > stopped. This is very likely to create a memory > leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) > and a value of type [java.lang.Integer] (value [0]) but failed > to remove it when the web application was stopped. > This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) > and a value of type [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@3a3396c1]) > but failed to remove it when the web application > was stopped. This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.Unicode$2@72ab5b9c]) and > a value of type > [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@10ee76c1]) > but failed to remove it when the web application > was stopped. This is very likely to create a > memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) > and a value of type [java.util.ArrayList] (value []) but failed to > remove it when the web application was stopped. > This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) > and a value of type [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17b68196]) > but failed to remove it when the web application > was stopped. This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) > and a value of type [java.lang.Boolean] (value [false]) but > failed to remove it when the web application was > stopped. This is very likely to create a memory > leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) > and a value of type [java.lang.Integer] (value [0]) but failed > to remove it when the web application was stopped. > This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) > and a value of type [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@4ef5ab03]) > but failed to remove it when the web application > was stopped. This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type > [java.lang.ThreadLocal] (value > [java.lang.ThreadLocal@33d3a0bf]) and a value of > type > [org.springframework.security.context.SecurityContextImpl] (value > [org.springframework.security.context.SecurityContextImpl@ffffffff: > Null authentication]) but failed to remove it when > the web application was stopped. This is very > likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.Unicode$2@72ab5b9c]) and > a value of type > [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@62ae7a74]) > but failed to remove it when the web application > was stopped. This is very likely to create a > memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.validation.HibernateDomainClassValidator$1@27f687c7]) > and a value of type [java.util.ArrayList] (value []) but failed to > remove it when the web application was stopped. > This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.io.FastByteArrayOutputStream$Cached$1@2a4c2e50]) > and a value of type [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@2ce98849]) > but failed to remove it when the web application > was stopped. This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$1@14413f02]) > and a value of type [java.lang.Boolean] (value [false]) but > failed to remove it when the web application was > stopped. This is very likely to create a memory > leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.codehaus.groovy.grails.orm.hibernate.support.HibernatePersistenceContextInterceptor$2@478fa6b1]) > and a value of type [java.lang.Integer] (value [0]) but failed > to remove it when the web application was stopped. > This is very likely to create a memory leak.Apr 24, 2011 8:35:49 PM > org.apache.catalina.loader.WebappClassLoader > clearThreadLocalMapSEVERE: The web application created a > ThreadLocal with key of type [null] (value > [org.elasticsearch.common.io.stream.CachedStreamOutput$1@2808d32b]) > and a value of type [org.elasticsearch.common.thread.ThreadLocals.CleanableValue] (value > [org.elasticsearch.common.thread.ThreadLocals$CleanableValue@17f287a8]) > but failed to remove it when the web application > was stopped. This is very likely to create a memory leak. > > I know that ES has nothing to be with Tomcat, > but indeed my web application which uses ES is > deployed in Tomcat, so I was wondering if anyone > has a clue on whether I should just ignore these > messages or pay them some attention, and how to > proceed. > > Thanks. ---
### Author: ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system) #### Post date: [July 6, 2017, 4:07am UTC](https://discuss.elastic.co/t/tomcat-and-severe-messages-in-the-output/4284/4 "2017-07-06T04:07:39Z")