Method overriding and method overloading are two different concepts in Java that are used to achieve polymorphism, one of the core concepts in Object-Oriented Programming (OOP). However, they differ in terms of implementation and usage.
Method overriding is the process by which a subclass provides a different implementation of the method that is already defined in its superclass. The method in the subclass has the same name, return type, and parameters as the method in the superclass. The method in the subclass should also have the same or broader accessibility than the method in the superclass. This allows the subclass to provide a specific behavior while using the functionality of the superclass.
For example:
```class Animal {
public void makeSound() {
System.out.println("Animal is making a sound");
}
}
class Dog extends Animal {
public void makeSound() {
System.out.println("Dog is barking");
}
}
Animal animal = new Dog();
animal.makeSound();
```
In this example, the Animal class has a method called makeSound(). The Dog class extends the Animal class and overrides the makeSound() method with its own implementation. However, when the makeSound() method is called on the animal object, the output will be "Dog is barking" instead of "Animal is making a sound". This is because the makeSound() method in the Dog class overrides the makeSound() method in the Animal class.
Method overloading refers to the process of defining multiple methods with the same name in the same class, but with different parameters. The parameters can differ in their type, order, or number. The overloaded methods can have different return types as well, but this does not affect the method overloading process.
For example:
```class Calculator {
public int add(int num1, int num2) {
return num1 + num2;
}
public double add(double num1, double num2) {
return num1 + num2;
}
}
Calculator calculator = new Calculator();
System.out.println(calculator.add(1, 2));
System.out.println(calculator.add(2.5, 3.5));
```
In this example, the Calculator class has two methods with the same name, but with different parameters. The first method takes two integers as parameters and returns their sum, while the second method takes two doubles as parameters and returns their sum. When these methods are called, the compiler determines which method to execute based on the number and types of the parameters passed to the method.
The main difference between method overriding and method overloading is that method overriding is used to provide a specific implementation of a method in a subclass, while method overloading is used to define multiple methods with the same name in a class for different parameter definitions. In method overriding, the method signature (name, return type, and parameters) must be the same in both the superclass and subclass. In method overloading, the method signature must be different in terms of parameter types, order, or number.
Here are some key differences between method overriding and method overloading:
Method Overriding | Method Overloading |
---|---|
The method in the subclass should have the same name, return type, and parameters as the method in the superclass. | The method in the same class should have the same name, but different parameters (type, order, or number). |
The method in the subclass should have the same or broader accessibility than the method in the superclass. | The access modifiers can be same or different but it shouldn't be less restrictive than the access modifier of the overridden method. |
It is used to provide a specific implementation of a method in a subclass. | It is used to define multiple methods with the same name in a class for different parameter definitions. |
Method overriding and method overloading are two different concepts that are used to achieve polymorphism in Java. Method overriding is used to provide a different implementation of the method that is already defined in its superclass, while method overloading is used to define multiple methods with the same name in a class for different parameter definitions. Understanding the difference between these concepts is crucial for writing efficient and organized Java code.