Names like David, Michael, Gabriel, etc. are common in many European cultures, I assume that Germany is no exception.
What did Germans with Jewish names do in that period? Were they required to change their names? would they get in trouble for having them? Or was it just part of the Christian heritage for the nazis?
Before other responses come in, you might be interested in a previous response to a similar topic that deals with the rules concerning common Jewish names (or naming in general) in the Nazi Germany.