Strange window snapshots

[Michael Paus]

Hi,

I am just debugging a JavaFX application which behaves strangely. 
Occasionally I am getting
strange error messages like this:

2020-03-29 17:43:34.485 java[6134:499599] 
-[NSPersistentUIWindowSnapshotter 
writeWindowSnapshot:length:width:height:bytesPerRow:toFile:inDirectory:encryptingWithKey:uuid:checksum:fd:]: 
0 == ftruncate(fd, finalFileSize) failed on line 797: No such file or 
directory
2020-03-29 17:43:34.486 java[6134:499599] 
-[NSPersistentUIWindowSnapshotter 
writeWindowSnapshot:length:width:height:bytesPerRow:toFile:inDirectory:encryptingWithKey:uuid:checksum:fd:]: 
0 == ftruncate(fd, fileLength) failed on line 868: No such file or directory

I am wondering now who or what is trying to do window snapshots of my 
machine?
It seems I am only seeing this because of some error. Otherwise I would 
not have even
noticed this.

Can anybody here provide me with some insight?

I am on
macOS 10.14.6
OpenJDK 15-ea+14-561
OpenJFX 15-ea+2

Michael