Knowledge Base - FAQ
Question: My JVM is stuck in 2DHeadless mode and I need to be in X11 mode!This one took us days of troubleshooting to figure out.
Mike from www.jwebhosting.net described it best in a response to a mail from our support department:
I've confirmed your theory on my site. If you set the headless property to true before any awt graphics method is used (e.g. frame), YOU WILL SET THE LOCAL GRAPHICS MODE to 2DHeadless (headless graphic environment) which will NOT let you use any of the main containers such as frame. The local graphic mode will persist (setting headless to false will not do anything) until jvm/tomcat is restarted. When jvm/tomcat is started, headless is null. The first graphic method encountered will trigger the jvm to determine and set the local graphics mode. As long as the headless property is not true (either null or false), the local graphic mode will be set to the awt.X11GraphicsEnvironment which uses the xvfb x server emulator which provides the full set of awt graphics methods.
Last Modified: Nov 14, 2003