@Enigma I am from Germany, actually.
Regarding your issue I am afraid there is not much we can do about it. These versions of TripleA and Java have been running rock solid since November 2018 - without noticable crash reports. Those crashes that occurred have usually happened with an error report - so we had at least something to investigate in.
You can always safely install the latest pre-releases of TripleA from
https://github.com/triplea-game/triplea/releases
next to the current stable version.
So you could give that a try and see if your problem continues to happen.
Note that your opponent would need a pre-release, too, as the save-games of 1.9 are incompatible with those of 2.0.
All I can say is that I had an unexpected similar crash some days ago - that never happened before, too. As this occurred only once I did not further care, but as you now report this, too, I will give the developers a note of this issue, maybe they have an idea that further helps.
(cc: @redrum )