- People imprisoned for violent crimes may stay there for their whole life if they pose an ongoing threat to public safety.
So... Germany DOES have a life sentence. Kinda misleading to state it doesn't.
However we also have "forvaring", or detention, which is locking someone up to protect the public.
If you're sentenced to "forvaring", you're not let go at the end. Instead a commission will review your case and behavior, and determine if the "forvaring" needs to be extended or not. So while you can't get more than 11 years (IIRC) at a time, the sentence can be extended indefinitely.
The important point is that "forvaring" isn't mean to be a punishment, although I assume it might certainly feel like it. It's meant to protect the public from a dangerous individual.