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// Superclass
class Animal {
    private final String name;
    private final int    age;

Animal(String name, int age) {
        this.name = name;
        this.age  = age;
    }

public String getName() { return name; }
    public int    getAge()  { return age;  }

public String speak() { return "..."; }

public void introduce() {
        System.out.printf("I am %s, age %d. I say: %s%n", name, age, speak());
    }
}

// Subclass
class Dog extends Animal {
    private final String breed;

Dog(String name, int age, String breed) {
        super(name, age);      // must be first statement
        this.breed = breed;
    }

@Override
    public String speak() { return "Woof!"; }

@Override
    public void introduce() {
        super.introduce();     // reuse parent logic
        System.out.println("  Breed: " + breed);
    }
}

class Cat extends Animal {
    private boolean indoor;

Cat(String name, int age, boolean indoor) {
        super(name, age);
        this.indoor = indoor;
    }

@Override public String speak() { return indoor ? "Meow~" : "MEOW!"; }
}

public class InheritanceDemo {
    public static void main(String[] args) {
        Animal[] animals = {
            new Dog("Rex",   3, "German Shepherd"),
            new Cat("Misty", 5, true),
            new Cat("Tiger", 2, false)
        };
        for (Animal a : animals) {
            a.introduce();
        }

// instanceof check before downcast
        for (Animal a : animals) {
            if (a instanceof Dog d) {          // pattern variable (Java 16+)
                System.out.println(d.getName() + " is a dog");
            }
        }
    }
}