Exceptions silently swallowed in DnD listeners... but only on Windows, and even in latest 1.8u121 release... This appears to be a bug??
I've written up here http://stackoverflow.com/questions/43488321/javafx-silently-swallowing-exception-raised-in-drag-listeners/43535229#43535229 Short version.... if you have a handler that throws an exception, then this is silently swallowed, nothing seen in console... destination . setOnDragOver ( new EventHandler < DragEvent >() { public void handle ( DragEvent event ) { event . acceptTransferModes ( TransferMode . LINK ); String nullReference = null ; nullReference . toCharArray (); // cause an exception event . consume (); } }); My investigation so far.... It appears that native method WinDnDClipboard.push(Object[], int) - backed by GlassClipboard.cpp [1] swallows the exception silently. A call back to Throwable.getMessage() can be seen in the debugger but no exception is printed to the console. The Java 9 version of this file (http://hg.openjdk.java.net/openjfx/9-dev/rt/file/1a3f128518cd/modules/javafx.graphics/src/main/native-glass/win/GlassClipboard.cpp [2]) has an additional call to CheckAndClearException(env); as defined in Utils.cpp, however this is against RT-35400 which appears unrelated. This has not been backported to Java 8. Thanks, Adam Links: ------ [1] http://hg.openjdk.java.net/openjfx/8/master/rt/file/tip/modules/graphics/src/main/native-glass/win/GlassClipboard.cpp [2] http://hg.openjdk.java.net/openjfx/9-dev/rt/file/1a3f128518cd/modules/javafx.graphics/src/main/native-glass/win/GlassClipboard.cpp
