super() call:
=============

package JavaIO.AIT;

class Class1{ // parent class
	Class1(){
		System.out.println("This is the Parent Class Constructor without parameters.");
	}
}

class Class2 extends Class1{ // child class
	Class2(){
		System.out.println("This is the Child Class constructor without parameters.");
	}
}

public class MainClass {

	public static void main(String[] args) {
		Class2 c2 = new Class2();
	}

}
=====================================================

package JavaIO.AIT;

class Class1{ // parent class
	Class1(int x)
	{
		System.out.println("This is the parent class constructor with parameters.");
		System.out.println("x = "+x);
	}
}

class Class2 extends Class1{

	Class2(int x){
		super(x);
		System.out.println("This is the Child Class constructor without parameters.");
	}
	
}

public class MainClass {

	public static void main(String[] args) {
//		Class2 c2 = new Class2(120);
		Class2 c3 = new Class2(240);
	}

}
=======================================================
package JavaIO.AIT;

class A{
	// how many constructors? ans: 1
	// when there is no constructor in a class, JVM automatically add a constructor.
}

class B extends A{
	B(){
		System.out.println("This is Child class constructor without parameters");
	}
	
	B(int x)
	{
		System.out.println("This is the Child Class constructor with parameters.");
	}
}

public class MainClass {

	public static void main(String[] args) {
//		B bref = new B();
		B bref1 = new B(200);
	}

}
========================================================
this() call:
============
==> this() call can use to call the same class constructor.
==> as like super() call, the this() call also be the first statement in the constructor.
==> If a constructor with this() call, we cannot able to add/write super() call.
==> If a constructor with super() call, we cannot able to write this() call within the same constructor.

package JavaAIT.IO;

class A{
	A(){
		System.out.println("This is the Parent Class constructor with 0 parameters.");
	}
}

class B extends A{
	B(){
		this(100);
		System.out.println("This is the Child Class Constructor with 0 parameters.");
	}
	
	B(int x){
		System.out.println("This is the Child Class Constructor with parameter.");
	}
}

public class MainClass {

	public static void main(String[] args) {
		B bref = new B();
	}

}