Problem
Hudson got java.awt.headless problem
I installed Hudson in Ubuntu linux and run the Hudson in the tomcat6.
I open any Hudson page which is showing any trend chart. I get the following error on the page.
Graphics N/A Unable to access X. You need to run the web container in the headless mode. Add -Djava.awtheadless=true to VM.
I check the tomcat6 starting script, the JVM property java.awt.headless is set to true already.
I check through the Hudson's Manage Hudson->System Information page. It also shows the java.awtheadless is set to true.
Looking through the Tomcat logs, the following error can be found:
Solution (for Open JDK)
We had the same problem too using Hudson in Tomcat6 on Ubuntu 9.10 server.
Obviously graphics rendering needs access to font metrics. So check java /etc/java-6-openjdk/fontconfig.properties and install missing fonts. OpenJDK refers to DejaVu-Fonts. So type
sudo apt-get install ttf-dejavu
Restart Tomcat and enjoy graphics.
Solution (for Sun JDK)
I also had the same problem using Hudson in Tomcat 6 on Ubuntu 9.10 Server, but this time with Sun's JDK6.
I initially only installed the package 'sun-java6-jdk'. After seeing the above fonts error, I tried installing the 'sun-java6-fonts' package, but that didn't seem to solve my problem. I gave up trying to find the exact package I needed to get things working and just decided to remove what I had and reinstall the "whole shebang":
sudo apt-get remove sun-java6*
sudo apt-get install sun-java6*
Maybe a little brute'ish, but it worked. Hudson now makes all of its pretty charts.