Java Method Overriding

What is Method Overriding in Java: An Introduction

• The method must have the same name as in the parent class
• The method must have the same parameter as in the parent class.
• There must be an IS-A relationship (inheritance).

Basics of Java Method Overriding Technique

Distinguishing Between Overloading and Overriding in Java

class Animal {
	void walk() {
		System.out.println("The animal walks");
	}
}
class Cat extends Animal {
	void walk() {
		System.out.println("The cat walks");
	}
}

How to Apply Java Method Overriding

Fundamentals of Java Method Overriding Syntax

• Access Modifier of the overriding method (method of SubClass) can't be more restrictive than the overridden method (method of SuperClass).
• If the superclass method declares an exception, the subclass overridden method can declare the same, a subclass exception or no exception, but can't declare parent exception.
• If the superclass method doesn't declare an exception, subclass overridden method can't declare any checked exception.
• The overriding method must have the same return type (or subtype).

public class Vehicle{
   public void run(){
      System.out.println("Vehicle is running");
   }
}
public class Car extends Vehicle{
   public void run(){
      System.out.println("Car is running");
   }
}

Practical Java Method Overriding Examples

public class Mammal {
   public void eat() {
      System.out.println("Mammal eats");
   }
}
public class Cat extends Mammal {
   public void eat() {
      System.out.println("Cat eats rat");
   }
}

Step-by-Step Guide to Java Method Overriding

Exploring the Usage of Java Method Overriding

Common Uses of Java Method Overriding

• Logic modification: At times, you might need to implement logic in a subclass that's slightly different from the one provided in the superclass. Method overriding is a perfect fit for such scenarios where you can effectively modify the logic as per the needs of your subclass.
• Adding more functionality: Sometimes, in the subclass, you might want to extend the functionality of a method inherited from a superclass. Java Method Overriding allows you to extend the method's functionality without modifying the superclass method.
• Preventing modifications: If you want to restrict any further modifications to a method in a subclass, you can use the final keyword when declaring the method in a superclass. This effectively prevents the method from being overridden in any of its subclasses.

Java Method Overriding in Object-Oriented Programming

public class Shape {
   public void area() {
      System.out.println("Shape's area");
   }
}

public class Circle extends Shape {
   public void area() {
      super.area();  // calling superclass's area method
      System.out.println("Circle's area");
   }
}

Advantages of Java Method Overriding in Programming Projects

• Code Reusability: Using Java method overriding allows you to reuse code from a superclass, without needing to rewrite the entire method in the subclass. This saves effort and decreases the likelihood of errors.
• Flexibility: Method overriding provides flexible programming, allowing you to create a method in a subclass with the same name and signature as in the superclass, but with a different implementation. This allows the subclass to maintain its uniqueness.
• Support for Polymorphism: Method overriding is essential in supporting runtime polymorphism in Java. It allows an object to take many forms and enables a programmer to refer to a subclass object using a parent class reference, which is essential in dynamic method dispatch.
• Extensibility: Our program can be extended in terms of logic, sector and behaviour with the help of Java method overriding. As a result, you can extend a method's functionality without modifying the superclass method.