25. SOLID: Liskov Substitution Principle (LSP)

The Scenario

The Liskov Substitution Principle states that objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program.

Predict the output and identify if LSP is violated.

class Bird {
    void move() { System.out.println("Flying..."); }
}

class Ostrich extends Bird {
    @Override
    void move() {
        throw new UnsupportedOperationException("I can't fly!");
    }
}

public class Main {
    public static void main(String[] args) {
        Bird b = new Ostrich();
        try {
            b.move();
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}

Take Your Shot

Predicted Output

Type exactly what you think will be printed in the console.