从HeadlessGraphicsEnvironment.getDefaultScreenDevice抛出的java.awt.HeadlessException

Question

I need to do some image processing on a java server (Debian with java version "1.6.0_12"), and I am receiving java.awt.HeadlessException from my code:

java.awt.HeadlessException
    at sun.java2d.HeadlessGraphicsEnvironment.getDefaultScreenDevice(HeadlessGraphicsEnvironment.java:64)
    at WaxOn.getDefaultConfiguration(WaxOn.java:341)

Even when java.awt.headless is set to true (as evident by this code printing so):

if (!java.awt.GraphicsEnvironment.isHeadless())
{
    logger.warn("Headless mode is not enabled");
}
else
{
    logger.info("Headless mode");
}

This is the code that throws the exception:

public static GraphicsConfiguration getDefaultConfiguration()
{
    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice gd = ge.getDefaultScreenDevice();
    return gd.getDefaultConfiguration();
}

Any idea how to solve this?

Answer 1

When headless you don't have a screen device. The documentation is clear :

Throws: HeadlessException - if isHeadless() returns true

Answer 2

Your code appears to be getting the default graphics device configuration on a machine that doesn't have a usable graphic device. This doesn't make much sense, and is never going to work.

If you could explain why you are trying to do this (on a headless machine) we might be able to offer an alternative.