http://apurvagnihotri.blogspot.sg/2010/06/hashmap-vs-hashtable.html?m=1
Good and concise on hashmap, concurrenthashmap, hashtable
http://apurvagnihotri.blogspot.sg/2010/06/hashmap-vs-hashtable.html?m=1
Good and concise on hashmap, concurrenthashmap, hashtable