There are some additions to the Java Collection Framework.
I tried to find out but I could not drill down what is actually the difference between:
NavigableMap vs ConcurrentNavigableMap.
Is it only, that ConcurrentNavigableMap can be modified by different threads?
The key difference is that ConcurrentNavigableMap provides the additional ConcurrentMap methods to NavigableMap as well as the additional concurrent usage semantics of ConcurrentMap.