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Bugfix
Stackoverflow conversation:

Then if PersonenDetail2 objects are not being deleted first you have a
JPA provider bug, or you have a PersonenDetail2 entity that is not
listed still referencing the Addresse you are trying to remove. Check
that you have not removed any from the collection by querying for all
PersonenDetail2's referencing your addresse directly and comparing the
two collections. Also check that there aren't other references to
PersonenDetail2 in your model that might prevent them from being
deleted. - Chris

@Chris Thanks, this was the problem. I had two Person Entities for the
same Table Person (PersonDetail1 / PersonDetail2). When i chose Adresse
referencing PersonDetail2 to delete, it didn't have the referenced Table
from PersonDetail1. So i programmed a third Class Named PersonDetail3
that referenced all Tables. Changed Adresse to reference PersonDetail3
instead of PersonDetail2 and programmed AdressDetail2 that referenced
PersonDetail2. And now it works without any problems. - Claudia