19/11/24_Understanding Interfaces in Java | Syntax, Features, and Multiple Inheritance
Description:
In this video, we explore Interfaces in Java, a crucial concept for building flexible and reusable code. Learn how interfaces work, their syntax, and their role in achieving multiple inheritance in Java.
Key Topics Covered:
What is an Interface?
A user-defined data type declared using the interface keyword.
Example Syntax: interface I1 { }
Interfaces compile into .class files, just like classes.
Members in an Interface:
Variables are always public static final.
Methods are by default public abstract.
Inheritance and Implementation:
Interfaces cannot have subclasses using extends; instead, the implements keyword is used.
Any class implementing an interface must override all abstract methods unless the class is declared abstract.
Interfaces can inherit other interfaces using extends.
Multiple Inheritance:
How interfaces solve the problem of multiple inheritance in Java by allowing a class to implement multiple interfaces.
By the end of this video, you’ll have a clear understanding of interfaces, their syntax, and how to use them effectively in Java programming for cleaner and more modular code!
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Interface
• In Java an Interface is a User-Defined data type.
• Using interface keyword, we can declare an Interface.
Syntax: -interface I1{ }
Here, interface is a keyword and I1 is an interface name.
• Like in classes, we get a .class file for an interface after its successful compilation.
• In an interface we generally declare two different types of members which are Variable and Method.
• When we declare a variable in an interface then it will always be public static final.
• When we declare a method inside an interface then by default it will be public abstract.
• Unlike as in class, we cannot create a sub-class of an interface using extends keyword.
• In Java we have a dedicated keyword implements that can be used to create a sub-class of an interface.
• When we use a class to implement an interface then we have to override all the abstract methods of super interface into the sub class, alternatively we can declare that sub-class as an abstract class.
Using interface, we can easily achieve Multiple Inheritance.
An interface can also inherit other interfaces using extends keyword.
An interface can also inherit other interfaces using extends keyword.