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Difference between Abstract Class and Interface

Could you please explain Abstract Class and Interface with examples.
Also explain how this will be used in real time.
Asked by rajendra prasad | Aug 19, 2013 |  Reply now
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Main difference is methods of a Java interface are implicitly abstract and cannot have implementations.

A Java abstract class can have instance methods that implements a default behavior. Variables declared in a Java interface is by default final.

An abstract class may contain non-final variables.
Members of a Java interface are public by default.

A Java abstract class can have the usual flavours of class members like private,protected, etc..

Java interface should be implemented using keyword “implements”; A Java abstract class should be extended using keyword “extends”.

An interface can extend another Java interface only, an abstract class can extend another Java class and implement multiple Java interfaces.

A Java class can implement multiple interfaces but it can extend only one abstract class.

Interface is absolutely abstract and cannot be instantiated; A Java abstract class also cannot be instantiated, but can be invoked if a main() exists.

Aug 28, 2013