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Abstract class is a class which contain one or
more abstract methods, which has to be implemented by sub classes.
Interface is a Java Object containing method declaration and doesn't
contain implementation.
The classes which have implementing the
Interfaces must provide the method definition for all the
methods.
Abstract class is a Class prefix with a abstract keyword followed by Class definition. Interface is a Interface which starts with interface keyword.
Abstract class contains one or more abstract methods. where as Interface contains all abstract methods and final declarations.
Abstract classes are useful in a situation that Some general methods should be implemented and specialization behavior should be implemented by child classes. Interfaces are useful in a situation that all properties should be implemented.Differences are as follows:
- Interfaces provide a form of multiple inheritance. A class can extend only one other class.
- Interfaces are limited to public methods and constants with no implementation. Abstract classes can have a partial implementation, protected parts, static methods, etc.
- A Class may implement several interfaces. But in case of abstract class, a class may extend only one abstract class.
- Interfaces are slow as it requires extra indirection to to find corresponding method in in the actual class. Abstract classes are fast.
- Neither Abstract classes or Interface can be instantiated.
This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.