JavaAnonymous Class
Anonymous Class
Ananonymous class is a class without a name. It is created and used at the same time.
You often use anonymous classes tooverride methods of an existing class or interface, without writing a separate class file.
Here, we create an anonymous class that extends another class and overrides its method:
// Normal classclass Animal { public void makeSound() { System.out.println("Animal sound"); }}public class Main { public static void main(String[] args) { // Anonymous class that overrides makeSound() Animal myAnimal = new Animal() { public void makeSound() { System.out.println("Woof woof"); } }; // semicolon is required to end the line of code that creates the object myAnimal.makeSound(); }}The output will be:
Woof woofAnonymous Class from an Interface
You can also use an anonymous class to implement an interface on the fly:
// Interfaceinterface Greeting { void sayHello();}public class Main { public static void main(String[] args) { // Anonymous class that implements Greeting Greeting greet = new Greeting() { public void sayHello() { System.out.println("Hello, World!"); } }; greet.sayHello(); }}The output will be:
Hello, World!When to Use Anonymous Classes?
Use anonymous classes when you need to create a short class for one-time use. For example:
- Overriding a method without creating a new subclass
- Implementing an interface quickly
- Passing small pieces of behavior as objects
