SEVERE: Error listenerStart
Aug 22, 2017 12:29:40 PM org.apache.catalina.core.StandardContext start
SEVERE: Context [/rhn] startup failed due to previous errors
Aug 22, 2017 12:29:40 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: A web application appears to have started a thread named [RHN Message Dispatcher] but has failed to stop it. This is very likely to create a memory leak.

SEVERE: A web application created a ThreadLocal with key of type [null] (value [com.redhat.rhn.common.hibernate.ConnectionManager$1@745e8bf]) and a value of type [null] (value [null]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.



does anyone has a clue what is the cause of this?
thanks inadvance.

Read the "Question Guidelines" link in my posting signature. Unless you provide details, what do you think we will be able to help you with? You don't say what version of Red Hat, or give us any context at all for this fairly generic error message you've posted. I see references to catalina...are you using Tomcat? New installation? New problem? Just deploy a new WAR file?

Since you're using Red Hat Enterprise (by the RHN message), have you contacted Red Hat support for assistance??? You are PAYING FOR RHEL, RIGHT????

it is RH 6.9 tomcat 6 , spacewalk 2.6 , and no unfortunately , we are not paying for this functionality, we do for RH, but no support on this one.
starting service leads to this behaviour.

So again, if you're paying for Red Hat support, then call Red Hat and they can assist you with diagnostics.

And again, is this a new issue/server?? Have you deployed a new WAR file in Tomcat? What is it exactly you're trying to do when this happens??? Again, without details, we cannot help.