Interface is similar to a class which may contain method’s signature only but not bodies and it is a formal set of method and constant declarations that must be defined by the class that implements it.

Interfaces are useful for:

a)Declaring methods that one or more classes are expected to implement

b)Capturing similarities between unrelated classes without forcing a class relationship.

c)Determining an object’s programming interface without revealing the actual body of the class.

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28 May 2013