Dynamic Binding in Java

Dynamic binding in Java is a concept closely related to runtime polymorphism, and it refers to the process of determining the actual implementation of a method call at runtime rather than compile time.

It enables Java to select the appropriate method implementation based on the type of the object that the method is invoked on.

Dynamic binding is essential for achieving runtime polymorphism, where the correct method implementation is determined dynamically based on the runtime type of the object.

It allows Java to support subclass polymorphism, where a subclass can override a method inherited from its superclass with its specific implementation.

Here's how dynamic binding works in Java:

Method Overriding:

Dynamic binding relies on method overriding, where a subclass provides a specific implementation for a method that is already defined in its superclass.

The subclass method signature (name and parameters) must match that of the superclass method.

Object Type Determination:

When a method is called on an object, Java determines the actual type of the object at runtime. This is known as dynamic type determination.

Method Invocation:

Once the actual type of the object is determined, Java selects the appropriate method implementation based on the dynamic type of the object and executes it.

Example:

class Animal {
    void makeSound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    @Override
    void makeSound() {
        System.out.println("Dog barks");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Dog(); // Dynamic type determination
        animal.makeSound(); // Dynamic binding and method invocation
    }
}

We have an "Animal" class with a "makeSound" method.
We have a "Dog" subclass that overrides the "makeSound" method with a specific implementation.
In the main method, we create an object of type "Dog" but assign it to a variable of type "Animal".
When we call the "makeSound" method on the "animal" object, Java dynamically binds the method call to the "makeSound" implementation in the "Dog" class, even though the reference type is "Animal".

Note:

Dynamic binding enables Java to achieve runtime polymorphism and supports flexible and extensible object-oriented programming paradigms.

It allows for loose coupling between classes and promotes code reuse and maintainability.

<-- Runtime Polymorphism