Swing components wrapped with SwingComponent.wrap() are apparently not garbage collected. I'm attaching a program consisting of a JavaFX file and a Java file to reproduce. (To compile the Java file, I had to use javac -target "1.5").

The scenario of the test program is as follows. You have a JavaFX node that shows slides built with Swing, which are created, wrapped and set in the JavaFX node every time you press a button. The "slides" are artificially big memory consumers in the test program. When I ran it, it didn't even get to slide # 11. The output follows.

#freeMemory=1280656
#freeMemory=4634560
#freeMemory=3633200
#freeMemory=7493296
#freeMemory=2390248
#freeMemory=15404040
#freeMemory=10316832
#freeMemory=5202592
#freeMemory=20814208
#freeMemory=15690520
#freeMemory=10582320
#freeMemory=5474344
Exception in thread "AWT-EventQueue-1" java.lang.OutOfMemoryError: Java heap spa
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Exception in thread "AWT-EventQueue-1" java.lang.OutOfMemoryError: Java heap spa
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Exception in thread "AWT-EventQueue-1" java.lang.OutOfMemoryError: Java heap spa
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Exception in thread "AWT-EventQueue-1" java.lang.OutOfMemoryError: Java heap spa
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Exception in thread "AWT-EventQueue-1" java.lang.OutOfMemoryError: Java heap spa
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