ConcurrentHashMap vs Hashtable
ConcusrrentHashMap vs Hashtable
As per my understanding ConcusrrentHashMap provides all the features of hashtable. On top of that it provide extra important feature that Retrieval operations (including get) generally do not block, so may overlap with update operations (including put and remove).
So can anybody give a example where we hashtable can not be replace by ConcusrrentHashMap