Noting that updating UPM; Universal Plugin Manager results in the below capture;
I then reviewed the logs;
2020-02-13 10:35:29,026 ERROR [ThreadPoolAsyncTaskExecutor::Thread 73] c.a.plugin.osgi.factory.OsgiPlugin Unable to start the plugin container for plugin 'com.atlassian.upm.atlassian-universal-plugin-manager-selfupdate-plugin '
org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from URL [bundle://159.0:0/META-INF/spring/atlassian-plugins-component-imports.xml]; nested exception is java.lang.Illeg alStateException: The bundle is uninstalled.
Caused by: java.lang.IllegalStateException: The bundle is uninstalled.
2020-02-13 10:35:29,031 ERROR [ThreadPoolAsyncTaskExecutor::Thread 73] o.e.g.b.e.i.s.ExtenderConfiguration Application context refresh failed (NonValidatingOsgiBundleXmlApplicationContext(bundle=com.atlassian.upm.atlassian-un iversal-plugin-manager-selfupdate-plugin, config=osgibundle:/META-INF/spring/*.xml))
org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from URL [bundle://159.0:0/META-INF/spring/atlassian-plugins-component-imports.xml]; nested exception is java.lang.Illeg alStateException: The bundle is uninstalled.
Caused by: java.lang.IllegalStateException: The bundle is uninstalled.
2020-02-13 10:35:29,031 ERROR [ThreadPoolAsyncTaskExecutor::Thread 73] o.e.g.b.e.i.d.s.DependencyWaiterApplicationContextExecutor Unable to create application context for [com.atlassian.upm.atlassian-universal-plugin-manager- selfupdate-plugin], unsatisfied dependencies: none
org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from URL [bundle://159.0:0/META-INF/spring/atlassian-plugins-component-imports.xml]; nested exception is java.lang.Illeg alStateException: The bundle is uninstalled.
Caused by: java.lang.IllegalStateException: The bundle is uninstalled.
:: If I am reading the logs correctly, it appears that an addon was uninstalled. So hopefully this is a case where I can re-introduce the jar file into the ${BAMBOO_HOME}/plugins directory to resolve, but I am unclear where to find or how to re-introduce 'com.atlassian.upm.atlassian-universal-plugin-manager-selfupdate-plugin' to resolve this.
~ As an aside I note that there may also be an actionable item here that the plugin should perform some maintenance to re-introduce its requisites upon request.