This content originally appeared on DEV Community and was authored by Mukesh
Inheritance in Java – Reusing Code the Right Way
Inheritance is one of the core pillars of Object-Oriented Programming (OOP), and Java provides robust support for it. In simple terms, inheritance allows one class to acquire properties and behaviors (methods and fields) of another class, promoting reusability and cleaner code design.
What is Inheritance?
In Java, inheritance means when one object (or class) inherits or acquires all the features (fields and methods) of another object. This leads to the formation of an IS-A relationship — for example a Dog IS-A Animal.
This relationship is also known as a parent-child or superclass-subclass relationship.
class Animal {
void eat() {
System.out.println("This animal eats food");
}
}
class Dog extends Animal {
void bark() {
System.out.println("Dog barks");
}
}
Here, Dog inherits from Animal, so it can eat() and bark().
Why Use Inheritance in Java?
Java supports inheritance to promote:
Code Reusability
Common logic can be written once in a parent class and reused in child classes.Method Overriding
Child classes can override parent class methods to implement runtime polymorphism, enabling flexible behavior at runtime.
Syntax: Using the extends Keyword
Inheritance in Java is enabled using the extends keyword.
class Child extends Parent {
// additional fields and methods
}
Types of Inheritance in Java
Java supports several forms of inheritance:
1. Single Inheritance
One class inherits from one other class.
class A {
void display() {}
}
class B extends A {
void show() {}
}
2. Multilevel Inheritance
A chain of inheritance.
class A {
void display() {}
}
class B extends A {
void show() {}
}
class C extends B {
void print() {}
}
3. Hierarchical Inheritance
Multiple classes inherit from a single parent class.
class A {
void greet() {}
}
class B extends A {}
class C extends A {}
What about Multiple Inheritance?
Java does not support multiple inheritance with classes to avoid ambiguity issues (like the Diamond Problem). But it does support multiple through interfaces:
interface Printable {
void print();
}
interface Showable {
void show();
}
class Demo implements Printable, Showable {
public void print() {}
public void show() {}
}
Conclusion
Inheritance makes Java code cleaner, reusable, and extensible. It's a powerful feature that, when used wisely, helps build robust OOP-based systems.
This content originally appeared on DEV Community and was authored by Mukesh
Mukesh | Sciencx (2025-07-13T06:47:08+00:00) Mastering Inheritance in Java: A Beginner’s Guide to Code Reusability. Retrieved from https://www.scien.cx/2025/07/13/mastering-inheritance-in-java-a-beginners-guide-to-code-reusability/
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