Weird issue with DB plugin


Raising here in case it’s not specific to my setup.


  • I’m using Azul JRE with JavaFX instead of the bundled JRE

Issue summary: User performs a plugin update (doesn’t seem to be specific to a plugin) and then the DB nodes no longer load and may throw an error like:


Back in April we had a similar problem but it also knocked out the KNIME console. Looking through the KNIME logs what seemed to be happening is something was being updated and a dependency was no longer available. In April the bottom of the chain was a log4j 1.7 dependency.

The current Chain is DB plugin can’t load because kerberos plugin can’t load because:

Caused by: org.osgi.framework.BundleException: Exception in org.knime.kerberos.KerberosPlugin.start() of bundle org.knime.kerberos.
at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(
at org.eclipse.osgi.internal.framework.BundleContextImpl.start(
at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(
at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(
at org.eclipse.osgi.container.Module.doStart(
at org.eclipse.osgi.container.Module.start(
at org.eclipse.osgi.framework.util.SecureAction.start(
at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(
… 121 more
Caused by: java.lang.NoClassDefFoundError: org/apache/log4j/lf5/LogLevelFormatException
at org.knime.kerberos.api.KerberosProvider.ensureInitialized(
at org.knime.kerberos.KerberosPlugin.start(
at org.eclipse.osgi.internal.framework.BundleContextImpl$
at org.eclipse.osgi.internal.framework.BundleContextImpl$
at java.base/ Method)
at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(
… 128 more
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.lf5.LogLevelFormatException cannot be found by org.knime.kerberos_4.5.0.v202111291611
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(
at java.base/java.lang.Clas

Full log section:

db-error.log (40.3 KB)

When this happened in April I had assumed it was related to some of the more complex internal integrations we have (mostly around integrating JavaFX for some custom cell rendering). I stripped out all EclipseFX and re-did the javafx integration without needing any additional external update sites.

After rebuilding out KNIME install we could then install updates again without it breaking.

A user has just done an update and again the database nodes have broken. It looks again to be dependencies of the plugin are breaking during the update.

The current fix we have is to uninstall the DB plugin and re-install it.

I do still have a somewhat custom setup so it may be an error of my making so not really expecting a solution to be provided. If I can think of a way to recreate on a vanilla KNIME install and it occurs there I will update.




Hi @swebb,

To me this looks like an issue with an incomplete update. We switched out the log4j version we ship with 4.6 to be based on reload4j. Reload4j does not contain the classes mentioned missing in the error message. The kerberos plugin needs an update, but it should be installed when upgrading from 4.5 to 4.6. I’ll investigate this further.

This confirms that it is an upgrade issue related to the kerberos plugin, thank you for reporting.


Ah I suspect what’s happened is I’m in the middle of the upgrade to 4.6 and have updated the internal develop branch composite sites to point at 4.6. So a user on 4.5 was able to install a 4.6 plugin without upgrading the KNIME platform to 4.6.

Thanks for the info :slight_smile:


Ah well that explains it :smiley:

1 Like

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.