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

Member Operator:-
    
This operator is also called as dot operator and it will represents
 the members of a package or class.

Syntax:- packagename.classname

Eg:- java.lang.System
     java.lang.String

 Every class have variables and members, we are using dot operator to represent 
the variable of a class and method of a class.


Syntax 1:-

  Variables of a class

classname.variable name

Eg:- System . out
     System . err

Syntax 2:-
 Methods of a class

classname.method name

Eg:- Math . Sqrt()