How does creating a instance of class inside of the class itself works?

Question

What makes it possible to create a instance of class inside of the class itself?

public class My_Class
 {

      My_Class new_class= new My_Class();
 }
         


        

Answer 1

The main thing I always see myself creating an instance from within the class, is when I am trying to reference a non-static item in a static context, such as when I am making a frame for a game or whatever, I use the main method to actually set up the frame. You can also use it for when there is something in a constructor that you want to set (like in the following, I make my JFrame not equal to null):

public class Main {
    private JFrame frame;

    public Main() {
        frame = new JFrame("Test");
    }

    public static void main(String[] args) {
        Main m = new Main();

        m.frame.setResizable(false);
        m.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        m.frame.setLocationRelativeTo(null);
        m.frame.setVisible(true);
    }
}