Confusion with interfaces

Question

Hi ,
What is the advantage over using interface. I mean , suppose
public interface Calculator
int add();
int sub();
int div();
int mul();
Now
public class Calculation implements Calculator
// will implement all method of Calculator interface
The same thing i can achieve with abstract class.

Answer 1

Prem wrote:
What is the advantage over using interface. I mean , suppose Well a Google of "advantages of using interfaces" threw up [url http://artofsoftwarereuse.com/2010/04/24/5-advantages-of-using-interfaces-for-reusable-assets/]this page, which gives 5 pretty good ones.
...The same thing i can achieve with abstract class.Yes, but an abstract class imposes a hierarchy that may not be desirable (hopefully, you've already been warned about overusing inheritance); it also (usually) imposes an implementation which may not be suitable for everyone.
PS: Didn't you already ask this question?
I believe I suggested you look at AbstractList as an example of a good pattern for an abstract class (ie, as a skeleton implementation of an interface).
Winston