Inheritance

Tags: #◇Computer Science #◇CCPROG3 #◇Inheritance #◇Code Snippets #◇M5

◇Key Definitions

Inheritance is an OOP principle where a new class (subclass) acquires the properties and behaviors (fields and methods) of an existing class (superclass).

◇Theoretical Framework

Inherited members can be used as-is, overridden, or hidden. Java supports single inheritance of state (a class can only extend one superclass) but multiple inheritance of type (a class can implement multiple interfaces). Enhances code reusability and establishes an "is-a" relationship.

◇Code Implementation

// Superclass
class Vehicle {
    protected String brand = "Ford";
    
    public void honk() {
        System.out.println("Tuut, tuut!");
    }
}

// Subclass extending Vehicle
class Car extends Vehicle {
    private String modelName = "Mustang";
    
    public void printDetails() {
        System.out.println(brand + " " + modelName);
    }
    
    // Overriding the superclass method
    @Override
    public void honk() {
        System.out.println("Beep, beep!");
    }
}

◇Syntax Breakdown

extends: Keyword used to inherit from a class. super: Keyword used to refer to the immediate parent class object. @Override: Annotation to indicate that the child class method is over-writing its base class method. protected: Access modifier allowing subclasses to access the member.

◇Complexity Analysis

Inheritance structures create a virtual method table (vtable) for dynamic method dispatch. Calling overridden methods has a negligible O(1) overhead. Deep inheritance trees can make code difficult to maintain and trace (the "yo-yo problem").

◇References & Navigation

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