I occasionally see the following warning messages on Mac OS X 10.9.5 when exiting a JavaFX program using the red 'X' in the window decoration:

I got the following two message when exiting the Canvas GUIMark2 bitmap test.

Java has been detached already, but someone is still trying to use it at -[GlassRunnable run]:/Users/kcr/javafx/8u-kcr/jfx/rt/modules/graphics/src/main/native-glass/mac/GlassApplication.m:93
0 libglass.dylib 0x0000000120c94b24 -[GlassRunnable run] + 164
1 Foundation 0x00007fff8dd697ce __NSThreadPerformPerform + 229
2 CoreFoundation 0x00007fff916205b1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
3 CoreFoundation 0x00007fff91611d29 __CFRunLoopDoSources0 + 441
4 CoreFoundation 0x00007fff916113ef __CFRunLoopRun + 831
5 CoreFoundation 0x00007fff91610e75 CFRunLoopRunSpecific + 309
6 java 0x0000000103555480 CreateExecutionEnvironment + 871
7 java 0x000000010355120c JLI_Launch + 1952
8 java 0x00000001035574dd main + 101
9 java 0x0000000103550a64 start + 52
Java has been detached already, but someone is still trying to use it at -[GlassRunnable dealloc]:/Users/kcr/javafx/8u-kcr/jfx/rt/modules/graphics/src/main/native-glass/mac/GlassApplication.m:107
0 libglass.dylib 0x0000000120c94c99 -[GlassRunnable dealloc] + 121
1 Foundation 0x00007fff8dd69820 __NSThreadPerformPerform + 311
2 CoreFoundation 0x00007fff916205b1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
3 CoreFoundation 0x00007fff91611d29 __CFRunLoopDoSources0 + 441
4 CoreFoundation 0x00007fff916113ef __CFRunLoopRun + 831
5 CoreFoundation 0x00007fff91610e75 CFRunLoopRunSpecific + 309
6 java 0x0000000103555480 CreateExecutionEnvironment + 871
7 java 0x000000010355120c JLI_Launch + 1952
8 java 0x00000001035574dd main + 101
9 java 0x0000000103550a64 start + 52