Class, Object and Constructor

1. Class. 

Class - is a user defined blueprint or prototype from which objects are created. It represents the set of properties or methods that are common to all objects of one type. 

2. Block - is a set of code enclosed within curly braces {} within any class , method, or constructor. 

There are two types of block in Java : static Block, instance (non-static) Block.

3. Constructor.

Constructor - is a similar to method that invoked when an object of the class is created. Konstruktorun return tipi olmur. Eger biz ozumuz konstruktor yaradiriqsa o zaman Java ozu default konstruktor yaratmir. Konstuktor hemiwe instance block-dan sonra iwe duwur. 

Exercise 1:

public class Main {

    static {
        System.out.println("This is static block");
        Main main = new Main();
    }

    {
        System.out.println("This is instance block");
    }

    public Main() {
        System.out.println("This is a constructor");
    }

    public static void main(String[] args) {
        System.out.println("This is a main method");

Output: 

This is static block
This is instance block
This is a constructor
This is a main method

Exercise 2:

public class Main {

    static {
        System.out.println("This is static block");
        Main main = new Main();
    }

    {
        System.out.println("This is instance block");
    }

    public Main() {
        System.out.println("This is a constructor");
    }

    public static void main(String[] args) {
        System.out.println("This is a main method");
        Main main = new Main();
Output:
This is static block
This is instance block
This is a constructor
This is a main method
This is instance block
This is a constructor