Thank you for promptly responding. The outputs of the commands follow in attached files.
Meantime with the help of the "scientific guess" method I have found that the problem persists only when I use Awesome window manager. And it turned out that there are issues with some other Java applications using that WM either. As the mainstream developer of Awesome WM refuses to support version 3.4 and have a habit to render unusable configuration files from one minor version to another, I found it more efficient to move out of that otherwise very decent but so poorly managed window manager. Taking into the account that the developing of 3.4 branch of Awesome have been stalled, posting the bug there also doesn't have a much sence (I might be wrong though). Sorry for the noise.
jabref-1.log
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jabref-2.log
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jabref-3.log
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