Unlike in the U.S. credit cards are not a thing here in Germany.
I understand that might have been the case in the past, but it is now 2017!
In the UK where I am from, the law makes credit card issuers jointly responsible with the seller for anything bought with a credit card. So if anything goes wrong and you cannot reclaim the money from the seller, you can reclaim the whole amount from the card issuer. Therefore it is foolish not to use a credit card for purchases.
The law may not give you that protection in Germany (I don't know), but you can certainly get a credit card in Germany, and you will find it very difficult to travel internationally without one.