when constructor is called in java code example

Example 1: what is constructor in java

A constructor is a special method used to initialize objects in java.
we use constructors to initialize all variables in the class 
when an object is created. As and when an object
is created it is initialized automatically with the help of 
constructor in java.
  
We have two types of constructors:
Default Constructor
Parameterized Constructor

public classname(){
}
public classname(parameters list){
}

Example 2: calling this in constructor java

In Java another constructor of the same class can be called from a
  constructor via this().
 Note however that this has to be on the first line.