Skip to main content

Java Exception Handling MCQ Test

  Loading…

Multilevel Inheritance – Method Overriding

Multilevel inheritance and method overriding are two important concepts in object-oriented programming, especially in Java. Let's discuss each of them:

Multilevel Inheritance:

Multilevel inheritance refers to a scenario where a derived class inherits properties and behavior from a base class, and another class then inherits from this derived class. This creates a chain of inheritance, where each class inherits from the one preceding it.


For example:


class Animal {

    void eat() {

        System.out.println("Animal is eating");

    }

}


class Dog extends Animal {

    void bark() {

        System.out.println("Dog is barking");

    }

}


class Labrador extends Dog {

    void color() {

        System.out.println("Labrador is golden in color");

    }

}


public class Main {

    public static void main(String[] args) {

        Labrador labrador = new Labrador();

        labrador.eat();   // Inherited from Animal

        labrador.bark();  // Inherited from Dog

        labrador.color(); // Specific to Labrador

    }

}


In this example, the `Labrador` class inherits from the `Dog` class, which in turn inherits from the `Animal` class. This demonstrates multilevel inheritance.


Method Overriding:

Method overriding occurs when a subclass provides a specific implementation of a method that is already defined in its superclass. The method in the subclass has the same signature (name and parameters) as the one in the superclass, thereby replacing or overriding the behavior of the superclass method.


For example:


class Animal {

    void sound() {

        System.out.println("Animal makes a sound");

    }

}


class Dog extends Animal {

    void sound() {

        System.out.println("Dog barks");

    }

}


public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        dog.sound(); // This will print "Dog barks" instead of "Animal makes a sound"

    }

}


In this example, the `Dog` class overrides the `sound()` method defined in the `Animal` class, providing its own implementation.


Method Overriding in Multilevel Inheritance:

Method overriding can also occur in multilevel inheritance, where a subclass overrides a method that it inherits from its superclass, and subsequent subclasses in the hierarchy can further override the method.


class Animal {

    void sound() {

        System.out.println("Animal makes a sound");

    }

}


class Dog extends Animal {

    void sound() {

        System.out.println("Dog barks");

    }

}


class Labrador extends Dog {

    void sound() {

        System.out.println("Labrador growls");

    }

}


public class Main {

    public static void main(String[] args) {

        Labrador labrador = new Labrador();

        labrador.sound(); // This will print "Labrador growls" because Labrador overrides the sound() method

    }

}


In this example, the `Labrador` class overrides the `sound()` method inherited from the `Dog` class, which itself overrides the `sound()` method from the `Animal` class.

Comments

Popular posts from this blog

Passing and Returning Objects in Java Methods

Passing and Returning Objects in Java Methods In Java, objects can be passed as parameters to methods and returned from methods just like other primitive data types. This allows for flexibility and the manipulation of object state within methods. Let's explore how passing and returning objects work in Java. Passing Objects as Parameters When you pass an object as a parameter to a method, you are essentially passing a reference to that object. This means that changes made to the object inside the method will affect the original object outside the method.  Example: class Car {     String model;     Car(String model) {         this.model = model;     } } public class CarProcessor {     // Method to modify the Car object     static void modifyCar(Car car, String newModel) {         car.model = newModel;     }     public static void main(String[] args) {       ...

Why is String[] args necessary in main() method in Java?

  Why is String[] args necessary in main() method in Java? In Java, the main method serves as the entry point for the program. The correct syntax for the main method is: public static void main (String[] args) { System.out.println( "Hello, Java!" ); } 🔹 Breaking it down: public → Accessible from anywhere. static → No need to create an object of the class to run it. void → No return value. main → Special method recognized by the JVM as the starting point. String[] args → Stores command-line arguments (optional but required by JVM). Why Can't We Skip String[] args ? JVM looks for main(String[] args) When you run a Java program, the JVM searches for the main method with exactly this signature : public static void main (String[] args) If you change or remove String[] args , the JVM cannot find the correct main() method and throws a runtime error (NoSuchMethodError). Java Specification Requires It The Java Language Specification (JLS) defines that main...