A DESCRIPTION OF THE PROBLEM :
A Canvas instance calls createBufferStrategy(2) when setting headless=true will trigger a ClassCastException.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
java -Djava.awt.headless=true HeadlessCanvas

ACTUAL VS EXPECTED BEHAVIOR :
ACTUAL -
Exception in thread "main" java.lang.ClassCastException: class sun.java2d.HeadlessGraphicsEnvironment cannot be cast to class sun.java2d.SunGraphicsEnvironment (sun.java2d.HeadlessGraphicsEnvironment and sun.java2d.SunGraphicsEnvironment are in module java.desktop of loader 'bootstrap')
at java.desktop/java.awt.Component.createBufferStrategy(Component.java:3878)
at java.desktop/java.awt.Canvas.createBufferStrategy(Canvas.java:201)
at java.desktop/java.awt.Component.createBufferStrategy(Component.java:3808)
at java.desktop/java.awt.Canvas.createBufferStrategy(Canvas.java:176)
at HeadlessCanvas.main(HeadlessCanvas.java:7)
EXPECTED -
IllegalStateException or HeadlessException

---------- BEGIN SOURCE ----------
import java.awt.*;
public class HeadlessCanvas {
    public static void main(String args[]) {
        Canvas c = new Canvas();

        try {
            c.createBufferStrategy(2);
        } catch (HeadlessException e) {
            // Expected behavior
        }
    }
}
---------- END SOURCE ----------