What is similarities/difference between an Abstract class and Interface?
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. Similarities: • Neither Abstract classes or Interface can be instantiated.
