1) Collection -
A group of integers, strings and objects,etc together...
You can add different data types to this, u can call it non-generic collection
you need to go through overhead of type conversion.
2) Generic - Collection of certain data types.
We need to define the datatype this Collection would hold.
It would be type safe and avoid run time type conversion problems with non-
generic counter part.
3) HashTable - Collection of certain types with KEY and VALUE of defined types.
Each Key of defined type would map a defined Value.