Inheritance

Inheritance

A subclass extends a parent class, inheriting its fields and methods:

class Animal {
    String name;
    Animal(String name) { this.name = name; }
    String speak() { return name + " makes a sound"; }
}

class Dog extends Animal {
    Dog(String name) { super(name); }  // call parent constructor

    @Override
    String speak() { return name + " barks"; }  // override
}

Animal a = new Dog("Rex");
System.out.println(a.speak());  // Rex barks

Key Points

• extends declares inheritance
• super(args) calls the parent constructor (must be first line)
• @Override marks overridden methods (optional but good practice)
• Java has single inheritance for classes

Polymorphism

An Animal reference can hold any subclass:

Animal[] pets = {new Dog("Rex"), new Cat("Luna")};
for (Animal a : pets) {
    System.out.println(a.speak());  // calls the right version
}

Your Task

Create Animal, Dog, and Cat classes. Dog.speak() appends "!" to the parent's result. Print each animal's speak() as shown.