• Two Important Differences Between Interfaces and Abstract Classes
• Interface or Abstract Class

When to Use Interfaces

Two Important Differences Between Interfaces and Abstract Classes

• 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.

Interface or Abstract Class

• These two differences usually direct the choice.
• If multiple inheritance is important or even useful interfaces are used.
• Abstract class lets you define some or all of the implementation.
• Any major class you expect to be extended should be an implementation of an interface.