The original issue was logged under:
The fix for concurrent conversion operation failure was working until 7.8.0, when we updated the Java slides version to the latest 15.9.0, the fix no longer works, the sample application attached with the previously logged issue is same, using the following function:
Presentation pres = new Presentation(inFile);
pres.saveToPdf(inFile + “.pdf”);
This application works fine if 7.8.0 is used, switching to 15.9.0 causes crash again.