Java reference

@Override

Marks a method that overrides a method of a parent class or interface. The compiler checks that it really does.

Available since: Java 5

Syntax

@Target(METHOD) @Retention(SOURCE) public @interface Override

Examples

Overriding a parent's method:

class Animal {
    String sound() {
        return "...";
    }
}
 
class Cat extends Animal {
    @Override
    String sound() {
        return "Meow";
    }
}
 
void main() {
    Animal pet = new Cat();
    IO.println(pet.sound());
}

Output:

Meow

A typo in the name: without the annotation you would get a new method, with it a compile error:

class Animal {
    String sound() {
        return "...";
    }
}
 
class Cat extends Animal {
    @Override
    String sond() {
        return "Meow";
    }
}
 
void main() {
    IO.println(new Cat().sound());
}

Output:

Main.java:8: error: method does not override or implement a method from a supertype

Notes

The annotation is optional, but it is always used: it protects against typos and wrong signatures. A classic mistake is equals(Cat other) instead of equals(Object other): that is an overload, not an override, and @Override catches it at once. It works for interface methods too, and for toString() and hashCode() from Object. It does not end up in the compiled class.

In the tutorial

Annotations — Annotations in Java — @Override, @Deprecated, @FunctionalInterface, @SuppressWarnings, declaring your own annotation, @Retention, @Target and reading annotations at run time.

Thanks for reading!