Override rules

Learn @Override and its rules.

Override and @Override

When you override a method, adding the @Override annotation is a good habit. It tells the compiler "I intend to override this method." If the signature has a typo, you get a compile error; this catches silent bugs.

Do not confuse override with overload. Overload defines a new method with the same name but a different parameter list; it does not use dynamic dispatch. Override replaces the parent method.

Calling the parent with super

Sometimes you want to call the parent version of a method you overrode. super.method() does that. For instance super.area() runs the parent's area method; you can use its result inside the child method.

This is especially useful in the template method pattern: the parent provides an algorithm skeleton, and subclasses customize some steps while keeping the skeleton via super.

Exercise Use override + super to build a sound

Define class Animal with a String sound() { return ""; } method. Define class Dog extends Animal that overrides sound with @Override and returns super.sound() + "Woof";. In main, assign with Animal a = new Dog(); and print System.out.println(a.sound());.

Show example solution

class Animal {
    String sound() { return ""; }
}

class Dog extends Animal {
    @Override
    String sound() { return super.sound() + "Woof"; }
}

public class Main {
    public static void main(String[] args) {
        Animal a = new Dog();
        System.out.println(a.sound());
    }
}

Test yourself

Which of the following is NOT override?
- A subclass method marked @Override with matching signature
- Widening a protected parent method to public
- A new method with the same name but different parameters
- Implementing an abstract method in a concrete subclass
Show answer

A new method with the same name but different parameters — Same name with different parameters is overload, not override.

Add the override annotation

class Dog extends Animal {
    ____
    String sound() { return "Woof"; }
}

Show answer

class Dog extends Animal {
    @Override
    String sound() { return "Woof"; }
}

Match the override and overload concepts

@Override

Marks override intent
overload

Same name, different parameters
super.method()

Calls the parent method
final

Blocks override

Next lesson: Abstract reference

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