If we have same method name in the super class as well as 
in the sub class, then the method in the subclass is said 
to override the method in the super class.

override methos have same method name with same 
signature.which methods are apper in super class to sub 
class.

Overriding means, In a derived class, if we include same
method name, with same number & types of parameters and
return type as a method already defined in the base class,
then the method is said to be Overridden.

base class:

class Circle {
protected double radius;

public double getArea() {
return Math.PI*radius*radius;
   }//this method returns the area of the circle
}

derived class:

class Cylinder extends Circle {

protected double length;

public double getArea() { // method overriden here
return 2*super.getArea()+2*Math.PI*radius*length;
    }//this method returns the cylinder surface area
}

According to J2ee Compleet reference java:
I Think the  answer is that
Overriding means the : In inheritance  If we Declare the
(Public of default)  Method in the superclass Similarly we 
declare the method with the same name ,Same type,same 
number of parameters.but the Body of the method May 
different When We Instansiate child class and access it 
then child's method will called if u want to call super's 
overriden method then use the [super()] method to access it 
in child  for this read [Java compleete reference's 
Chapter#8] u will find reasonable answer