症状

Cannot insert JIRA issues or other JIRA issues in Confluence

atlassian-confluence.log に次のエラーが返される。

ERROR [http-8090-3] [[Standalone].[localhost].[/confluence].[servlet-module-container-servlet]] log Servlet.service() for servlet servlet-module-container-servlet threw exception
java.lang.NoClassDefFoundError: Could not initialize class sun.awt.X11GraphicsEnvironment

原因

X11 forwarding enabled on ssh session with server containing JIRA or Confluence instance.

ソリューション

1. Stop Confluence and JIRA.
2. Open a non X11 forwarding shell on server containing JIRA and Confluence.
3. Restart Confluence and JIRA from the new shell.