Multilevel inheritance

Multilevel inheritance is a type of inheritance in Java where a derived class inherits properties from a base class, which in turn is derived from another base class. In other words, a subclass can inherit from a superclass, and the superclass can itself be a subclass of another superclass, and so on. This creates a chain of inheritance where each class in the chain inherits properties from its direct superclass and its indirect superclass.

Syntax

class A {
    // code to be executed
};

class B extends A {
    // code to be executed
};

class C extends B {
    // code to be executed
};

Code Example 1 – constructors

This code defines four classes: Animal, Dog, Cat, and MultilevelInheritance.

Animal, Dog, and Cat are classes that are related by inheritance, with Dog being a subclass of Animal, and Cat being a subclass of Dog.

The Animal class has a constructor that prints the message “This is an Animal”. The Dog class has a constructor that prints the message “This is a Dog”. The Cat class has a constructor that prints the message “This is a Cat”. Since Cat is a subclass of Dog, which is a subclass of Animal, it inherits the constructors of both Dog and Animal.

The MultilevelInheritance class has a main method that creates a new Cat object called obj.

class Animal {
    Animal() {
        System.out.println("This is an Animal");
    }
};

class Dog extends Animal {
    Dog() {
        System.out.println("This is a Dog");
    }
};

class Cat extends Dog {
    Cat() {
        System.out.println("This is a Cat");
    }
};

class MultilevelInheritance {
    public static void main(String[] args) {
        Cat obj = new Cat();
    }
}

Output

This is an Animal
This is a Dog
This is a Cat

Code Example 2 – methods

This code defines four classes: Animal, Dog, Cat, and MultilevelInheritance.

Animal, Dog, and Cat are classes that are related by inheritance, with Dog being a subclass of Animal, and Cat being a subclass of Dog.

The Animal class has a method printAnimal() that prints the message “This is an Animal”. The Dog class has a method printDog() that prints the message “This is a Dog”. The Cat class has a method printCat() that prints the message “This is a Cat”. Since Cat is a subclass of Dog, which is a subclass of Animal, it inherits the methods of both Dog and Animal.

The MultilevelInheritance class has a main method that creates a new Cat object called obj and calls its printAnimal(), printDog(), and printCat() methods.

class Animal {
	public void printAnimal() {
		System.out.println("This is an Animal");
	}
};

class Dog extends Animal {
	public void printDog() {
		System.out.println("This is a Dog");
	}
};

class Cat extends Dog {
	public void printCat() {
		System.out.println("This is a Cat");
	}
};

class MultilevelInheritance {
	public static void main(String[] args) {
		Cat obj = new Cat();
		obj.printAnimal();
		obj.printDog();
		obj.printCat();
	}
}

Output

This is an Animal
This is a Dog
This is a Cat