Java Dynamic Method Dispatch Interactive Guide

The Golden Dispatch Rule:

Reference Type (Type on the left) determines what methods are accessible at compile time.
Actual Object Type (Type on the right) determines which implementation runs at runtime.

📜 Core Rules of Dispatch

Reference Assignment
A superclass reference can refer to a subclass object: SuperClass obj = new SubClass();
Runtime Resolution
When an overridden method is called, Java inspects the actual object on the heap at runtime (not the reference type) to decide which method version to execute.
Compile-Time Constraint
You can only call methods that exist in the reference type class. If a method exists only in the child class, calling it using a parent reference causes a compilation error.

💻 Class Hierarchy Code

class Animal {
    void makeSound() {
        System.out.println("Some generic sound");
    }
}

class Dog extends Animal {
    void makeSound() {
        System.out.println("Woof! Woof!");
    }
}

class Cat extends Animal {
    void makeSound() {
        System.out.println("Meow! Meow!");
    }
}

⚙️ Dynamic Dispatch Simulator

Select an object type to instantiate under the Animal reference, then dispatch makeSound().

Execute statement: Animal myAnimal = new

Stack Memory (Compile Time)

Reference Name: myAnimal

Reference Type: Animal

⬇️ Points to object on Heap at runtime

Heap Memory (Runtime)

Actual Instance: new Animal()

Resolved Method: Animal.makeSound()

> Console Output will appear here when you click "myAnimal.makeSound();"