Germany's eastern neighbor - Russia

I’ve been checking the news today and I found out that either Poland ceased to exist, it was dismembered for the fourth time in the history, or Mr. Kohl and President Putin had a really great vodka party last night.
What Helmut Kohl said was that “Russia is, and is going to remain Germany’s most important eastern neighbor”. President Putin just started bear-hugging him as they do it over there.
Now I ask, since when Germany shares borders with Russia?
Hopefully history doesn’t repeat itself again this time…