Stream:-
      Stream is a intermediator among input, output and user. All streams 
are represented by class in java.io package.
Streams are classified into two types
1) Input Stream
2) Output Stream

Input Stream:
   Data is received from input devices in sequences then it is called "input stream"
 or "Source Stream"
EX:- Keyboard

Output Stream:
   Data is passed output devices then it is called "output stream" or "Destination stream".
EX:- Monitor