DAY11 Multiple Inheritance and Interfaces:

4. Multiple Inheritance Java does not support multiple inheritance with classes to avoid ambiguity caused by the Diamond Problem. However, interfaces allow a class to inherit behavior from multiple sources. This is particularly useful in real-time scenarios where a class needs to combine functionalities from different independent modules.

Interface 1:Logger

Interface 2: Database Operations:

Class to implement above interfaces

• Combines logging and database functionalities.
• Implements test logic with shared utilities.

Class to demonstrate the Multiple Inheritance:

In the provided Example we have something as interface:

What is Interface and abstract classes and method?

An interface specifies methods that a class must implement but does not provide the actual implementation of those methods. Interfaces are key to achieving abstraction and multiple inheritance in Java.

• Interface methods do not have a body - the body is provided by the "implement" class
• On implementation of an interface, you must override all of its methods
• Interface methods are by default abstract and public
• Interface attributes are by default public, static and final
• An interface cannot contain a constructor (as it cannot be used to create objects)

Now you may have a question how Logger Interface in Multiple Inheritance has implementation in itself:

That is because Interface 1 (Logger) has a default method that provides the implementation for the log method.

Default Methods in Interfaces

Default Methods in Interfaces:

• Before Java 8, interfaces could only contain abstract methods, meaning any class implementing an interface had to provide the implementation.
• From Java 8 onwards, interfaces can have default methods with a body (implementation). This allows the interface to define a common behavior while still being extensible by the implementing classes.

Purpose of Default Methods:

• They enable backward compatibility in Java. New methods can be added to existing interfaces without breaking the classes that already implement the interface.
• Allow interfaces to provide reusable functionality, reducing the need for implementing classes to redefine common behavior.

Let's see what are abstract methods and classes tomorrow. Happy Learning :)