[Geoserver-users] WebappClassLoader error

Dear Geoserver Users,

after a successful startup of GeoServer, some minutes later, I get the message below in my catalina.out logfile.
I am using Ubuntu 14.04 with Java Runtime 1.7.0_75-b13.
What does that ClassLoader error mean?

Does that mean that the server is not working properly? Currently I cannot test it, because it seems that my Apache ajp mapping does not work properly. I get a blank page when I call the IP/geoserver. In the firebug console I can see that the page is not found “404 Not Found”.

Apr 13, 2015 7:01:29 AM org.apache.catalina.loader.WebappClassLoader loadClass
INFORMATION: Illegal access: this web application instance has been stopped already. Could not load com.google.common.base.Platform. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1612)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
at com.google.common.base.Ticker$1.read(Ticker.java:60)
at com.google.common.cache.LocalCache$Segment.cleanUp(LocalCache.java:3437)
at com.google.common.cache.LocalCache.cleanUp(LocalCache.java:3858)
at com.google.common.cache.LocalCache$LocalManualCache.cleanUp(LocalCache.java:4797)
at org.geoserver.security.auth.GuavaAuthenticationCacheImpl$1.run(GuavaAuthenticationCacheImpl.java:62)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

Thank you for your support.

Kind regards,
Christoph