OpenJDK on Ubuntu: Java Headless exception is caused by the incomplete Java installation.
Recent Ubuntu releases (10.04 LTS) show quite a nasty behavior when trying to start Java application: the application crashes on startup with Headless exception.
This is cause by the by default incomplete installation of OpenJDK. It is kind of present but missing some packages that are available on Ubuntu repository. On the discussions on the web I found people suggest to switch immediately to Oracle's proprietary java or even into Windows.
Unfortunately I had no time to copy stack trance and the exact name of the missing package - needed to fix the problem quickly and now is too late. But this is no any rocket since; the missing package is something like "java jre" - could be assumed to be the full installation rather than somehow stripped one that comes by default.
Check packages in the repository if you have this problem. Hope you fill fish out this message with Google. Good luck!