Annotations.java

//! Annotations is used to provide extra information about a program.
//! Annotations provides metadata to class/methods.
//! Annotations starts with a '@'.
//! Annotations are helpful for detecting errors. Example : @override annotations will make sure that there are no typos while overriding a method.

@FunctionalInterface // * Used to ensure an interface is a functional interface
interface myFunctionalInterface {
    void thisMethod();
}

class CellPhone {
    public void ring() {
        System.out.println("CellPhone Ringing!");
    }

    public void vibrate() {
        System.out.println("CellPhone Vibrating!");
    }
}

class SmartPhone extends CellPhone {
    @Override // * This is used to mark override elements in the child class
    public void ring() {
        System.out.println("SmartPhone Ringing!");
    }

    @Deprecated // * This annotations is used to mark deprecated method
    public int sum(int a, int b) {
        return a + b;
    }
}

public class Annotations {
    @SuppressWarnings("warnings!") // * Used to suppress the generated warnings by the compilers
    public static void main(String[] args) {
        // ? Create the instance of the SmartPhone
        SmartPhone sp = new SmartPhone();
        sp.ring();
        sp.vibrate();
        sp.sum(5, 8);
    }
}