Keywords:
super() – Calls the parent class constructor.
this – Refers to the current instance.
new – Creates objects dynamically.

Comparison:
Abstract Class – Has both abstract and concrete methods; cannot be instantiated.
Final Class – Cannot be extended; ensures fixed implementation.
Interface – Defines method signatures; supports multiple inheritance.

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1. Watch this tutorial alongside for a better understanding.

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2. This Keyword in Java:

public class ThisInJava {

	public static void main(String[] args) {
		
		Student obj = new Student("Amit");
		obj.display();

	}

}

class Student{
	
	String name;
	
	Student(String name){
		this.name = name;
	}
	
	void display() {
		System.out.println(this.name);
	}
	
}

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3. Super Keyword in Java:

class Animal{
	
	Animal(int a){
		System.out.println("Animal constructor is called!: " + a);
	}
	
	boolean isItAnAnimal = true;
	
	void sound() {
		System.out.println("It is animal sound!");
	}
	
}

class Dog extends Animal{
	
	Dog(){
		super(1);
		System.out.println("Dog constructor is called!");
	}

	boolean isItAnAnimal = false;
	
	void sound() {
		super.sound();
		System.out.println("It is dog sound!: " + super.isItAnAnimal);
	}
}


public class SuperInJava {

	public static void main(String[] args) {
		
		Dog obj = new Dog();
		obj.sound();
		
	}
}

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4. New Keyword in Java:

public class NewKeywordInJava {

	public static void main(String[] args) {
		
		String s1 = new String("ABC");
		String s2 = "ABC";
		
		CarService obj1 = new CarService("Red");
		
		CarService obj2 = new CarService("Green");
		
		CarService obj3 = new CarService("Black");
		
		System.out.println("obj1: " + obj1.color);
		System.out.println("obj2: " + obj2.color);
		System.out.println("obj3: " + obj3.color);
		
	}

}

class CarService{
	String color;
	
	CarService(String color){
		this.color = color;
	}
}

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5. Abstract Class, Final Class and Interface in Java

public class FinalAndAbstractClassinJava {

	public static void main(String[] args) {
		
		class1 obj = new class1();
		
	}

}

abstract class ABC{
	abstract void display1();
	
	void display2() {
		
	}
}

class ABCD extends ABC{
	void display1() {
		
	}
}

//100% abstract class
interface interface1{
	void display1();
	
	abstract void display2();
}

interface interface2{
	abstract void display3();
}


class ABCDE implements interface1, interface2{
	public void display1() {
		
	}
	
	public void display2() {
		
	}
	
	public void display3() {
		
	}
}

final class class1{
	public void display4() {
		System.out.println("display4");
	}
}

class class2 extends class1{//error
	
}

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