Best way to detect whether code is running in an application server java

Question

For a J2EE bean I am reusing code that was developed for a java swing application. JOptionPane.showMessageDialog() is unfortunately commonly used. Most occurenc

Answer 1

I just tested this with OpenJDK Runtime Environment (IcedTea 2.4.3) (Gentoo build 1.7.0_45-b31) on Linux, and I find that unset DISPLAY was also sufficient to make isHeadless() (and isHeadlessInstance()) return true.

So, this method doesn't just tell you whether AWT was forced to ignore the system's graphics capabilities, but rather whether your process has access to graphics capabilities at all.

Example:
The code is running on some box that has no display card (that's probably what you want to know) so you can always check the system property if for some reason you want to know whether headless mode was forced.

Answer 2

Make sure the server is started with

java -Djava.awt.headless=true

Most servers should be started that way by default. Then you can check:

boolean headless_check = GraphicsEnvironment.isHeadless();

More details on headless available here: