headless Java : Java Glossary

2007-12-13 by Roedy Green ©1996-2009 Canadian Mind Products
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headless Java

When Java is implemented on a very small device, a keyboard, mouse or AWT graphics support may not be available. You will get a HeadlessException if you try to instantiate one of the AWT classes. You code can determine if keyboard, mouse and screen are available with:

import java.awt.GraphicsEnvironment;
...
// true if missing keyboard, mouse or screen.
// false if full keyboard, mouse and GUI screen support available.
boolean barebones = GraphicsEnvironment.isHeadless();

You can simulate a headless environment by setting the java.awt.headless system property:

-Djava.awt.headless=true

Sun’s Javadoc on the isHeadless method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

Sun on headless

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