Fix "Could not initialize class sun.awt.X11GraphicsEnvironment" on insert of Jira gadget into Confluence DC

Platform Notice: Data Center Only - This article only applies to Atlassian apps on the Data Center platform.

Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.

*Except Fisheye and Crucible

Symptoms

Can't insert Jira issues or other Jira issues in Confluence

The following appears in the atlassian-confluence.log:

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

Cause

X11 forwarding is enabled on the SSH session with the server containing a Jira or Confluence instance.

Resolution

  1. Stop Confluence and Jira.

  2. Open a non-X11 forwarding shell on the server containing Jira and Confluence.

  3. Restart Confluence and Jira from the new shell.

Updated on September 25, 2025

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