JabRef 5.0-beta.532--2020-03-04--8111707
Linux 4.9.0-12-amd64 amd64
Java 13.0.2

• [X ] I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

When searching full text documents for entries without keys, the found pdf files are all named "default.pdf" (overwriting the previously existing default.pdf file)

Steps to reproduce the behavior:
1.Select a few entries which do not have a BibTeX key
2. Menu Tools > Search full text documents online

--> For all entries, the field "file" has a link to the same file "default.pdf".

Suggestion: before starting to search for full-text documents, check that the entries have a BibTeX key.