I downloaded 4.2 to try out, and the file link feature still does not work properly. In jabref 3 if I click “get fulltext” it immediately links to my files on my hard-drive. On 4.2 with the same bibtex file - it croaks and I have to manually shut jabref down (same problem in Jabref 4.1 which I report ages ago).
So I am back to jabref 3 until this is fixed - my workflow entails getting hard copies of papers I am working on and linking them to my bibtex. Jabref 3 is very good- jabref 4 at the moment is still not ready for researchers who have large bibtex files.
I am running this on opensuse 42.2 with java 8.
Many thanks in advance.