The Meliora Testlab plugin documentation for its Pipeline step was previously available at https://www.jenkins.io/doc/pipeline/steps/meliora-testlab . When the Pipeline steps doc generator was upgraded from Jenkins core 2.474 to Jenkins core 2.481, the doc generator step for the plugin started failing with a null pointer exception and the Pipeline steps reference documentation was no longer available for the plugin.

That transition in Jenkins core is the transition from Jakarta EE 8 to Jakarta EE 9. The failure message from the Pipeline steps doc generator job is:

21:42:09  [WARNING] Cannot instantiate fi.meliora.testlab.ext.jenkins.TestlabNotifier$DescriptorImpl 
21:42:09  java.lang.NullPointerException: Cannot invoke "jakarta.servlet.ServletContext.getAttribute(String)" because "c" is null
21:42:09  	at hudson.util.PluginServletFilter.getInstance(PluginServletFilter.java:87)
21:42:09  	at hudson.util.PluginServletFilter.addFilter(PluginServletFilter.java:115)
21:42:09  	at hudson.util.PluginServletFilter.addFilter(PluginServletFilter.java:134)
21:42:09  	at PluginClassLoader for meliora-testlab//fi.meliora.testlab.ext.jenkins.TestlabNotifier$DescriptorImpl.<init>(TestlabNotifier.java:682)

Other Pipeline steps retain their documentation across that version transition. The Meliora Testlab plugin seems to be the only plugin affected.

Refer to https://github.com/jenkinsci/meliora-testlab-plugin/pull/17 for the pull request proposing to modernize the plugin to current Jenkins versions and current Java versions.