Im was trying out the VAqua Look and Feel on MacOS Catalina, its included in classpath and I call it like this
UIManager.setLookAndFeel("org.violetlib.aqua.AquaLookAndFeel");
but then my code fails with
4/11/2019 13.16.22:GMT:UncaughtExceptionHandler:uncaughtException:SEVERE: An unexpected error has occurred com.apple.laf.ScreenMenu.addMenuListeners(Lcom/apple/laf/ScreenMenu;J)J on thread main, please report to support @jthink.net
java.lang.UnsatisfiedLinkError: com.apple.laf.ScreenMenu.addMenuListeners(Lcom/apple/laf/ScreenMenu;J)J
at com.apple.laf.ScreenMenu.addMenuListeners(Native Method)
at com.apple.laf.ScreenMenu.addNotify(ScreenMenu.java:254)
at java.awt.Menu.addNotify(Menu.java:183)
at com.apple.laf.ScreenMenu.addNotify(ScreenMenu.java:234)
at com.apple.laf.ScreenMenuBar.add(ScreenMenuBar.java:285)
at com.apple.laf.ScreenMenuBar.addSubmenu(ScreenMenuBar.java:223)
at com.apple.laf.ScreenMenuBar.addNotify(ScreenMenuBar.java:66)
at java.awt.Frame.addNotify(Frame.java:483)
at java.awt.Window.pack(Window.java:807)
at com.jthink.songkong.ui.MainWindow.setupScreen(MainWindow.java:322)
at com.jthink.songkong.cmdline.SongKong.guiStart(SongKong.java:1494)
at com.jthink.songkong.cmdline.SongKong.finish(SongKong.java:1602)
at com.jthink.songkong.cmdline.SongKong.main(SongKong.java:1627)
any ideas ?
Although the lib is opensrc it does not seem to be hosted on github, although the author has other libs on github
EDIT: I checked the website and it seems that the author for the website has extended support for macOS Catalina. I suggest you try downloading and using the LaF now.
I don't think the VAqua look and feel is supported on Catalina, but I maybe wrong about the source of the error. Below are screenshots from the VAqua website.