Skip to content

2024

  • in DevOps
  • 1 min read

How to Fix the No X11 Display Error With Java Applications on Ubuntu 24.04 LTS

On my newly upgraded Ubuntu 24.04 LTS I got this error when I started a Java application:

Exception in thread "main" java.awt.HeadlessException: No X11 DISPLAY variable was set, or no headful library support was found, but this program performed an operation which requires it,

at java.desktop/sun.java2d.HeadlessGraphicsEnvironment.getDefaultScreenDevice(HeadlessGraphicsEnvironment.java:58) at foo.lj.a(Unknown Source) at foo.lj.(Unknown Source)

Little SQL Server Tricks: Rename Default Constraints

One would assume that renaming a default constraint should work the same way as renaming a primary key. For some unknown reason that was not the case as I had to fix the (dynamically generated) names of default constraints. The format that worked at last was this one:

1
exec sp_rename N'SCHEMA.NAME_OLD', N'NAME_NEW' , N'OBJECT';

Enforce the Current JavaScript File in ASP.NET

There is not much more annoying that fixing a bug in a JavaScript file and then find problems in production because the browsers of your users cached the old file. While the first reaction is to disable all caching, there is a better way in ASP.NET: append the file version to the JavaScript file name.

My Highlights of NDC Oslo 2024

With 2300 attendees this year's NDC Oslo was a bit smaller than the one in 2023. Nevertheless, I liked it much more and think the talks were a lot better.

Only two talks I attended finished after just 40 minutes and both times I could go to another talk and still catch some helpful insights. I had only 3 talks that did not meet my expectations, the rest were good to great talks that offered a lot of helpful insights.

For once we did not have much luck with the weather at the traditional Oslo Fjord Cruise. It started with clouds and turned into a thunderstorm. Fortunately, the boat is built in such a way that you do not notice much of these conditions if you stay inside.