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BN 8.1 beta throw an exception while starting an aborts. No .netbeans/8.1beta directory, starting from a "clean session". This warning appears in the log: Could not install look and feel [GTK look and feel - com.sun.java.swing.plaf.gtk.GTKLookAndFeel] Later came the exception java.lang.ClassCastException: javax.swing.plaf.synth.DefaultSynthStyleFactory cannot be cast to com.sun.java.swing.plaf.gtk.GTKStyleFactory at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.initSystemColorDefaults(GTKLookAndFeel.java:1334) at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.getDefaults(GTKLookAndFeel.java:309) at org.netbeans.core.windows.view.ui.MainWindow.logLookAndFeelUsage(MainWindow.java:903) at org.netbeans.core.windows.view.ui.MainWindow.init(MainWindow.java:176) at org.netbeans.core.windows.WindowSystemImpl.init(WindowSystemImpl.java:71) at org.netbeans.core.GuiRunLevel.initializeMainWindow(GuiRunLevel.java:156) at org.netbeans.core.GuiRunLevel.run(GuiRunLevel.java:98) at org.netbeans.core.startup.Main.start(Main.java:320) at org.netbeans.core.startup.TopThreadGroup.run(TopThreadGroup.java:123) at java.lang.Thread.run(Thread.java:745) Using OpenJDK Runtime Environment (build 1.8.0_66-internal-b01) from Debian Testing on a Debian Stretch/Sid OS. Workaround: specify a different LaF $ netbeans -- laf Metal
This is most probably not a NetBeans issue but reassigning to Platform for appropriate evaluation.
Looks like some GTK issue in OpenJDK. Do not have such problems with 8.2 dev builds on JDK 8.