Variables and methods of super class can be overridden in subclass. 
In case of overriding , a subclass
object call its own variables and methods. Subclass cannot 
access the variables and methods of
superclass because the overridden variables or methods hides the 
methods and variables of super class.
But still java provides a way to access super class members even if 
its members are overridden. Super is
used to access superclass variables, methods, constructors.
Super can be used in two forms :
1) First form is for calling super class constructor.
2) Second one is to call super class variables,methods.
Super if present must be the first statement.