I have some strange logs at startup of our XWiki instance (15.10.12 docker-tomcat-postgresql) that occur two times and that have been present for at least a couple past versions:
[XWiki initialization] ERROR c.x.x.p.XWikiPluginManager - Cannot initialize plugin [com.xpn.xwiki.plugin.svg.SVGPlugin]. This plugin will not be available.
java.lang.ClassNotFoundException: com.xpn.xwiki.plugin.svg.SVGPlugin
and
[XWiki initialization] ERROR c.x.x.p.XWikiPluginManager - Cannot initialize plugin [com.xpn.xwiki.plugin.diff.DiffPlugin]. This plugin will not be available.
java.lang.ClassNotFoundException: com.xpn.xwiki.plugin.diff.DiffPlugin
I would assume that these are some corrupted extension installs that linger around. I checked the extension manager with the intention to reinstall / delete. However, I did not find any indication of them being present and I do not really know how to proceed from here. While we do experience any problems during daily use I would like to have this fixed to keep the instance clean.
Any ideas what this could be, where I could look for more information or how I could fix it?
The plugins are the very old style to extend XWiki and are slowly removed and replaced by components.
One reason for this is that plugins can only be activated/deactivated via configuration file, which requires a restart.
If you can find the xwiki.cfg file for your instance (I forgot where it is for the docker install), you can edit the property xwiki.plugins:
#-# List of active plugins.
xwiki.plugins=\
com.xpn.xwiki.monitor.api.MonitorPlugin,\
com.xpn.xwiki.plugin.skinx.JsSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.JsSkinFileExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.JsResourceSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.CssSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.CssSkinFileExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.CssResourceSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.LinkExtensionPlugin,\
com.xpn.xwiki.plugin.feed.FeedPlugin,\
com.xpn.xwiki.plugin.mail.MailPlugin,\
com.xpn.xwiki.plugin.packaging.PackagePlugin,\
com.xpn.xwiki.plugin.svg.SVGPlugin,\
com.xpn.xwiki.plugin.fileupload.FileUploadPlugin,\
com.xpn.xwiki.plugin.image.ImagePlugin,\
com.xpn.xwiki.plugin.diff.DiffPlugin,\
com.xpn.xwiki.plugin.rightsmanager.RightsManagerPlugin,\
com.xpn.xwiki.plugin.jodatime.JodaTimePlugin,\
com.xpn.xwiki.plugin.scheduler.SchedulerPlugin,\
com.xpn.xwiki.plugin.mailsender.MailSenderPlugin,\
com.xpn.xwiki.plugin.tag.TagPlugin,\
com.xpn.xwiki.plugin.zipexplorer.ZipExplorerPlugin
Here you can remove the lines with the com.xpn.xwiki.plugin.svg.SVGPlugin and com.xpn.xwiki.plugin.diff.DiffPlugin, and the the error messages should no longer be present after the next restart.
It is not strictly necessary to remove the plugins from the config; if they do no longer exist, this will cause only the error message at startup and no further problems.
