maintainer-feedback requested: [Bug 264356] java/openjdk17: Exception with multi-screen setup

Bugzilla Automation <bugzilla@FreeBSD.org> has asked freebsd-java (Nobody)
<java@FreeBSD.org> for maintainer-feedback:
Bug 264356: java/openjdk17:  Exception with multi-screen setup
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=264356



--- Description ---
Starting in OpenJDK 17 (tested on FreeBSD), a call to
java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment() will cause a
program to throw java.lang.ExceptionInInitializerError if run on a
screen that is not the first screen, i.e., :3.0.

I am unsure how good the attached fix is, but it does prevent the crash.
Basically, the variable screens is null when run on another screen such
as :3.1.  As the only thing needed is the number of screens, I switched
it to use the already defined numScreens.

It is easy to duplicate using xephyr:
Xephyr :3 -screen 800x600 -screen 800x600

Running the attached java program on screen :3.0 will work.
Running it on screen :3.1 throws an exception:

Exception in thread "main" java.lang.ExceptionInInitializerError
	at
java.desktop/java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsE
nvironment.java:106)
	at GraphEnv.main(GraphEnv.java:18)
Caused by: java.lang.NullPointerException: Cannot read the array length because
"this.screens" is null
	at
java.desktop/sun.awt.X11GraphicsEnvironment.initDevices(X11GraphicsEnvironment.
java:235)
	at
java.desktop/sun.awt.X11GraphicsEnvironment.rebuildDevices(X11GraphicsEnvironme
nt.java:216)
	at
java.desktop/sun.awt.X11GraphicsEnvironment.<init>(X11GraphicsEnvironment.java:
201)
	at
java.desktop/sun.awt.PlatformGraphicsInfo.createGE(PlatformGraphicsInfo.java:36
)
	at
java.desktop/java.awt.GraphicsEnvironment$LocalGE.createGE(GraphicsEnvironment.
java:93)
	at
java.desktop/java.awt.GraphicsEnvironment$LocalGE.<clinit>(GraphicsEnvironment.
java:84)
	at
java.desktop/java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsE
nvironment.java:106)
	at GraphEnv.main(GraphEnv.java:18)
	at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAcce
ssorImpl.java:77)
	at
java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMe
thodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at
jdk.compiler/com.sun.tools.javac.launcher.Main.execute(Main.java:419)
	at jdk.compiler/com.sun.tools.javac.launcher.Main.run(Main.java:192)
	at jdk.compiler/com.sun.tools.javac.launcher.Main.main(Main.java:132)