Confluence won't start after plugin update
Asked by Paul Maina:

I updated a number of plugins and one of them froze Confluence. I have tried restarting the service a few times even in safe mode and even rebooted the server but no much luck. I am getting three errors that I have never seen before and Googling these is not yielding any fruits. Any assistance on these three errors?

First 2 are from the confluence log, last one is from catalina startup

2019-11-25 11:04:39,697 ERROR \[localhost-startStop-1\] \[atlassian.confluence.event.ConfluenceEventDispatcher\] run There was an exception thrown trying to dispatch event \[ThemeConfigurationSavedEvent \[saved=ThemeConfiguration \[configurationSchemaVersion=6, intranetName=\]\]\] from the invoker \[SingleParameterMethodListenerInvoker{method=public void net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver.onThemeConfigurationSavedEvent(net.seibertmedia.confluence.plugins.theme.configuration.entity.ThemeConfigurationSavedEvent), listener=net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver@cb49802} (timed)\]java.lang.RuntimeException: **Unable to resolve owner of loading collection** \[\[com.atlassian.confluence.core.ContentEntityObject.bodyContents#360453\]\] for second level caching. Listener: net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver event: net.seibertmedia.confluence.plugins.theme.configuration.entity.ThemeConfigurationSavedEvent

2019-11-25 11:04:55,941 ERROR \[lifecycle:thread-1\] \[sal.confluence.lifecycle.TenantAwareLifecycleManager\] triggerLifecycleAsTenant Unable to start component: com.atlassian.sal.confluence.lifecycle.MeasuringPluginUpgradeManager  
com.atlassian.plugin.util.Assertions$NullArgumentException: **Plugin key should not be null!**   
at com.atlassian.plugin.util.Assertions.notNull(Assertions.java:9)  
at com.atlassian.plugin.manager.ProductPluginAccessorBase.getPlugin(ProductPluginAccessorBase.java:146)  
at com.atlassian.plugin.manager.ForwardingPluginAccessor.getPlugin(ForwardingPluginAccessor.java:70)  
at com.atlassian.plugin.manager.EnabledModuleCachingPluginAccessor.getPlugin(EnabledModuleCachingPluginAccessor.java:39)  
at com.atlassian.plugin.manager.ForwardingPluginAccessor.getPlugin(ForwardingPluginAccessor.java:70)

2019-11-25 11:02:14,227 INFO \[localhost-startStop-1\] \[com.atlassian.c onfluence.lifecycle\] contextInitialized Starting Confluence 6.15.2 \[b uild 8100 based on commit hash 4410012ac87e845516b70bc69b6f7a893eabaa 5a\] - synchrony version 2.1.0-master-9d112c9d  
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".  
SLF4J: Defaulting to no-operation (NOP) logger implementation  
SLF4J: See <http://www.slf4j.org/codes.html#StaticLoggerBinder> for further details.  
Warning: validation was turned on but an org.xml.sax.ErrorHandler was not  
set, which is probably not what is desired. Parser will use a default  
ErrorHandler to print the first 10 errors. Please call  
the 'setErrorHandler' method to fix this.  
**Error: URI=null Line=1: Document is invalid: no grammar found.**   
**Error: URI=null Line=1: Document root element "atlassian-plugin", must match DOCTYPE root "null".**


Answers:
author: Johan Soetens _Dumblefy_
body: Hi Paul,

if it's a production instance, I'd recommend [contacting Atlassian Support](https://support.atlassian.com/)

Perhaps you could try [clearing the plugin cache](https://confluence.atlassian.com/confkb/how-to-clear-confluence-plugins-cache-297664846.html), have a look [at Confluence Startup Problems Troubleshooting](https://confluence.atlassian.com/confkb/confluence-startup-problems-troubleshooting-180846988.html) as well.

comments: author: Paul Maina
body: Thanks for the tip, I had cleared out the cache folders as the first solution. However, I have managed to get it back up and running. The problem is that it took about 30 minutes to start up.


author: Johan Soetens _Dumblefy_
body: Glad you're up and running again, Paul. That sure is a long boot time, might be worth investigating it further.

Have a nice day.


Tags: confluence-server

server