Java-Roadmap/inheritance.java at main · Derric01/Java-Roadmap · GitHub

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Inheritance
// Inheritance is the mechanism by which one class acquires the properties and features of another class. The class that inherits the properties is called as a sub-class (child class) while the class from which the property is inherited is called as the super-class (parent class).

// A child class inherits properties of parent class with the help of extends keyword.

// Syntax:

// class childClass extends parentClass {
// //any code
// }

// Inheritance can be further divided into the following types:
// Single level
// Multi-level
// Hierarchical
// Multiple
// Hybrid


// Multiple and hybrid inheritance is not directly supported in java, instead it is achieved through the use of interfaces in java.

// i. Single Inheritance
// When a single class inherits the attributes and methods of another class, it is known as single inheritance.


// Example:

// class FundamentalForce {
// void Force() {
// System.out.println("There are four fundamental forces.");
// }
// }

// class Gravitational extends FundamentalForce {
// void Gravity() {
// System.out.println("Fruits fall to the ground due to gravitational Force.");
// }
// }

// class SingleInheritance {
// public static void main(String[] args) {
// Gravitational G = new Gravitational();
// G.Force();
// G.Gravity();
// }
// }


// Output:

// There are four fundamental forces.
// Fruits fall to the ground due to gravitational Force.


// In this example, we see how class Gravitational can inherit the method of Its parent class (FundamentalForce). This is an perfect example of parent-child relationship.


// ii. Multi-level Inheritance
// When a class 3 inherits attributes and methods from class 2 which in turn inherits its attributes and methods from class 1, it is called a multi-level inheritance.

// It forms a child-parent-grandparent (or a parent-child-grandchild) relationship. Meaning that child inherits from the parent while the parent inherits from the grandparent.


// Example:

// class NuclearForce extends FundamentalForce {
// void Nuclear() {
// System.out.println("Nuclear Forces are of two types;");
// System.out.println("Strong Nuclear Force");
// System.out.println("Weak Nuclear Force");
// }
// }

// class StrongNuclearForce extends NuclearForce {
// void Strong() {
// System.out.println("Strong Nuclear Force is responsible for the underlying stability of matter.");
// }
// }

// class MultilevelInheritance {
// public static void main(String[] args) {
// StrongNuclearForce st = new StrongNuclearForce();
// st.Force();
// st.Nuclear();
// st.Strong();
// }
// }


// Output:

// There are four fundamental forces.
// Nuclear Forces are of two types;
// Strong Nuclear Force
// Weak Nuclear Force
// Strong Nuclear Force is responsible for the underlying stability of matter.

// In this example, we see how class StrongNuclearForce inherits the method of NuclearForce which in turn inherits the method of FundamentalForce. This is a classic example of a child-parent-grandparent relationship.


// iii. Hierarchical Inheritance
// Hierarchical inheritance is when two or more classes inherit from a single class. This can be easily visualized as a parent with more than one child. Here each child can inherit the properties of a parent.


// Example:

// class FundamentalForce {
// void Force() {
// System.out.println("There are four fundamental forces.");
// }
// }

// class Gravitational extends FundamentalForce {
// void Gravity() {
// System.out.println("Fruits fall to the ground due to gravitational Force.");
// }
// }

// class Electromagnetic extends FundamentalForce {
// void Particles() {
// System.out.println("The electromagnetic force acts between charged particles");
// }
// }

// class HierarchicalInheritance {
// public static void main(String[] args) {
// System.out.println("Child 1:");
// Gravitational G = new Gravitational();
// G.Force();
// G.Gravity();

// System.out.println();
// System.out.println("Child 2");
// Electromagnetic em = new Electromagnetic();
// em.Force();
// em.Particles();
// }
// }


// Output:

// Child 1:
// There are four fundamental forces.
// Fruits fall to the ground due to gravitational Force.

// Child 2
// There are four fundamental forces.
// The electromagnetic force acts between charged particles