Anonymous Class — brain.kamillobinski.dev

Anonymous class is a class without a name, used to instantate and override methods on the fly - often used for quick, one-time use.

Example

With Interface

Runnable r = new Runnable() {
    @Override
    public void run() {
        System.out.println("Running anonymously");
    }
};
 
r.run(); // "Running anonymously"

With Abstract Class

abstract class Animal {
    abstract void makeSound();
}
 
Animal animal = new Animal() {
    void makeSound() {
        System.out.println("Meow");
    }
};
 
anima.makeSound(); // "Meow"

Key Points

Created using new keyword.
Can extend a class or implement an interface.
Defined inline where you need the object.
No constructors (because the class has no name).
Used mostly in event handling, threading or short-term behavior injection.

Real-World Analogy

Like a temporary worker - shows up, does the job and disappears. No need for a full employee profile (class definition).

Tip

If you need a one-off implementation of an interface or abstract class, think anonymous class.
Also mention that it’s less common post Java 8 due to lambdas.

Parent: _OOP Advanced Tools