Java Inheritance

Definitions

Inheritance is a fundamental concept in object-oriented programming (OOP) languages like Java. It allows classes to inherit properties and behaviors from other classes, promoting code reusability and creating hierarchical relationships among classes.

This hierarchical relationship forms an "is-a" type of relationship, where a subclass "is a" specialized version of its superclass.

Syntax of Inheritance in Java

// Superclass
public class Superclass {
    // Fields, constructors, and methods
}

// Subclass inheriting from Superclass
public class Subclass extends Superclass {
    // Additional fields, constructors, and methods
}

Advantages Of Inheritance in Java

• Code Reusability: Inheritance allows for code reuse and reduces the amount of code that needs to be written. The subclass can reuse the properties and methods of the superclass, reducing duplication of code.
• Abstraction: Inheritance allows for the creation of abstract classes that define a common interface for a group of related classes. This promotes abstraction and encapsulation, making the code easier to maintain and extend.
• Class Hierarchy: Inheritance allows for the creation of a class hierarchy, which can be used to model real-world objects and their relationships.
• Polymorphism: Inheritance allows for polymorphism, which is the ability of an object to take on multiple forms. Subclasses can override the methods of the superclass, which allows them to change their behavior in different ways.

Inheritance Types in Java

Single Inheritance

In single inheritance, a sub-class is derived from only one super class. It inherits the properties and behavior of a single-parent class. Sometimes, it is also known as simple inheritance.

Multilevel Inheritance

In Multilevel Inheritance, a derived class will be inheriting a base class, and as well as the derived class also acts as the base class for other classes.

Hierarchical Inheritance

In Hierarchical Inheritance, one class serves as a superclass (base class) for more than one subclass.

Multiple Inheritance

In Multiple inheritances, one class can have more than one superclass and inherit features from all parent classes.

Hybrid Inheritance

It is a mix of two or more of the above types of inheritance.

Inheritance in Java Example

import java.io.*;
import java.lang.*;

class Resource
 {
   String address,name;

   void accept()
   {
         Console c=System.console();
         System.out.print("\tName...");
         name=c.readLine();
         System.out.print("\tAddress...");
          address=c.readLine();
  }
  void print()
   {
     System.out.println("Name is..>"+name);
    System.out.println("Address..."+address);
   }
}
class Student extends Resource
 {
   int sfee;
    void saccept()
    {
 System.out.println("Please Enter Student Details");
	       accept();
         Console c=System.console();
         System.out.print("\tStudent Fee..");
         sfee=Integer.parseInt(c.readLine());
   }

	void sprint()
	 {
	   print();
	   System.out.println("Fee is..."+sfee);
	System.out.println();
	  }
}
class Emp extends Resource
{
  int sal;
   void eaccept()
    {
      System.out.println("Please Enter Employee Details");
	       accept();
         Console c=System.console();
         System.out.print("\tEmployee Salary..");
         sal=Integer.parseInt(c.readLine());
	}
   void eprint()
   {
    print();
 System.out.println("Employee salary.."+sal);
	System.out.println();
   }
}

public class InheritanceDemo2
{
 public static void main(String args[])
  {
  	Student st=new Student();
	st.saccept();
    	 st.sprint();

	 Emp e=new Emp();
	  e.eaccept();
	  e.eprint();
  }
}