Object Oriented Programming Lecture 6: Interfaces

Interface Fields in Java

• The default access modifier for interface fields in Java is public static final.
• The implements keyword is used to implement an interface in Java.

Benefits of Default Methods

• A benefit of default methods in Java interfaces is that they allow developers to add new functionality to interfaces without breaking existing implementations.

Updating Interfaces

• The printDetails method is added to the Vehicle interface in the updated version.

Interface Field Access Modifiers

• The private and protected access modifiers are not allowed for fields in a Java interface.

Purpose of Interfaces

• The main purpose of an interface in Java is to define a contract that must be implemented by any class that implements it.

Interface Methods

• An interface can have concrete (non-abstract) methods, known as default methods, which provide a default implementation that can be overridden by implementing classes.

Implementing Multiple Interfaces

• A class can implement multiple interfaces in Java.

Interfaces vs Abstract Classes

• The main difference between an interface and an abstract class in Java is that an interface cannot have instance variables, while an abstract class can.

Implementing Interfaces

• If a class implements an interface in Java, it is required to provide an implementation for all the abstract methods declared in the interface.