None.

None.

Dictionary, Map & Hashtable all implement Map interface hence all of them uses keys to 

store value in the object.

Vectors are dynamic arrays, it contains many legacy methods that are not part of 

collection framework, and hence these methods are not present in ArrayList. But 

both are used to form dynamic arrays.

Bitset class creates a special type of array that holds bit values. This array can increase 

in size as needed.