Linux theme detection fails with gsettings Missing on 0.8.1

[Luh-code]

Description:

On some Linux installations, theme detection fails due to the absence of gsettings. This issue was observed starting from version 0.8.1 but not in 0.8.0. I suspect this isn't a new bug but rather an existing one that now logs properly due to the introduction of slf4j-simple in #123.

For more information, please see the related issue on this repository.

Steps to Reproduce:

1. Use a Linux system without gsettings installed
2. Run an application using version 0.8.1
3. Observe the logs indicating theme detection failure

Actual Behavior:
Theme detection fails with the following error:
java.io.IOException: Cannot run program "gsettings": error=2, No such file or directory

Expected Behavior:

• The application should gracefully handle the absence of gsettings or even provide an alternative theme detection method

Environment:

• OS: NixOS 24.11.20241105.411656 (Vicuna)
• Kernel: Linux 6.11.5-zen1
• WM: Hyprland
• Java Version: 21

Additional Context:

• Version 0.8.0 does not produce this issue; reverting to it resolves the problem.
• Error logs suggest the issue stems from jSystemThemeDetector
• Example logs from my system when trying to run this assignment:

> Task :Main.main()
[main] ERROR com.jthemedetecor.GnomeThemeDetector - Couldn't detect Linux OS theme
java.io.IOException: Cannot run program "gsettings": error=2, No such file or directory
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1089)
	at java.base/java.lang.Runtime.exec(Runtime.java:681)
	at java.base/java.lang.Runtime.exec(Runtime.java:491)
	at java.base/java.lang.Runtime.exec(Runtime.java:366)
	at com.jthemedetecor.GnomeThemeDetector.isDark(GnomeThemeDetector.java:57)
	at fopbot.GuiPanel.<init>(GuiPanel.java:87)
	at fopbot.KarelWorld.setVisible(KarelWorld.java:363)
	at fopbot.World.setVisible(World.java:28)
	at h03.Main.main(Main.java:17)
Caused by: java.io.IOException: error=2, No such file or directory
	at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
	at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:295)
	at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:225)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1126)
	... 9 more
[main] ERROR com.jthemedetecor.GnomeThemeDetector - Couldn't detect Linux OS theme
Caused by: java.io.IOException: error=2, No such file or directory

java.io.IOException: Cannot run program "gsettings": error=2, No such file or directory
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1089)
	at java.base/java.lang.Runtime.exec(Runtime.java:681)
	at java.base/java.lang.Runtime.exec(Runtime.java:491)
	at java.base/java.lang.Runtime.exec(Runtime.java:366)
	at com.jthemedetecor.GnomeThemeDetector.isDark(GnomeThemeDetector.java:57)
	at com.jthemedetecor.GnomeThemeDetector$DetectorThread.<init>(GnomeThemeDetector.java:111)
	at com.jthemedetecor.GnomeThemeDetector.registerListener(GnomeThemeDetector.java:85)
	at fopbot.GuiPanel.<init>(GuiPanel.java:108)
	at fopbot.KarelWorld.setVisible(KarelWorld.java:363)
	at fopbot.World.setVisible(World.java:28)
	at h03.Main.main(Main.java:17)
Caused by: java.io.IOException: error=2, No such file or directory
	at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
	at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:295)
	at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:225)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1126)
	... 11 more
[GTK Theme Detector Thread] ERROR com.jthemedetecor.GnomeThemeDetector - Couldn't start monitoring process 
java.io.IOException: Cannot run program "gsettings": error=2, No such file or directory
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1089)
	at java.base/java.lang.Runtime.exec(Runtime.java:681)
	at java.base/java.lang.Runtime.exec(Runtime.java:491)
	at java.base/java.lang.Runtime.exec(Runtime.java:366)
	at com.jthemedetecor.GnomeThemeDetector$DetectorThread.run(GnomeThemeDetector.java:121)
Caused by: java.io.IOException: error=2, No such file or directory
	at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
	at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:295)
	at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:225)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1126)
	... 5 more

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