Inheritance

what is inheritance?

1.The new class that is created is known as subclass (child or derived class) and the existing class from where the child class is derived is known as superclass (parent or base class).

2.Inheritance in Java is a process of acquiring all the behaviours of a parent object.

1. Single Inheritance

In single inheritance, a single subclass extends from a single superclass. For example,

The extends keyword is used to perform inheritance in Java. For example,

class Animal {
  // methods and fields
}

// use of extends keyword
// to perform inheritance
class Dog extends Animal {

  // methods and fields of Animal
  // methods and fields of Dog
}

practice program-1:

class aravind {

  // field and method of the parent class
  String name;
  public void work() {
    System.out.println("I am java developer");
  }
}

// inherit from aravind
class pavithran extends aravind {

  // new method in subclass
  public void display() {
    System.out.println("My name is " + name);
  }
}

class Main {
  public static void main(String[] args) {

    // create an object of the subclass
    pavithran details = new pavithran();

    // access field of superclass
    details.name = "suriya";
    details.display();

    // call method of superclass
    // using object of subclass
    details.work();

  }
}
output:
My name is suriya
I am java developer

Method overriding

the same method is defined in both the superclass and the subclass, then the method of the subclass class overrides the method of the superclass. This is known as method overriding.

program-2: Method overriding in Java Inheritance

class aravind {

  // field and method of the parent class
  String name;
  public void work() {
    System.out.println("I am java developer");
  }
}

// inherit from aravind
class pavithran extends aravind {
    
  // overriding the work() method
     public void work() {
    System.out.println(" No,I am python developer");
  }

  // new method in subclass
  public void display() {
    System.out.println("My name is " + name);
  }
}

class Main {
  public static void main(String[] args) {

    // create an object of the subclass
    pavithran details = new pavithran();

    // access field of superclass
    details.name = "suriya";
    details.display();

    // call method of superclass
    // using object of subclass
    details.work();

  }
}
output:
My name is suriya
 No,I am python developer

(TBD)-The final Keyword link below

https://www.w3schools.com/java/java_inheritance.asp

Assignment task:

https://github.com/aravind2040/java-program/blob/master/Assignment2.java

Reference:

https://www.programiz.com/java-programming/inheritance

https://www.w3schools.com/java/java_inheritance.asp

https://www.geeksforgeeks.org/inheritance-in-java/

https://www.mygreatlearning.com/blog/inheritance-in-java/