Java Swing : Frame construction inside Constructor

 //We can also write all the codes of creating JFrame, JButton and method call inside the java constructor.
   
    import javax.swing.*; 
    public class SwingInsideConstructor { 
    JFrame f; 
    SwingInsideConstructor(){ 
    f=new JFrame("Music Book");//creating instance of JFrame 
             
    JButton b=new JButton("Open");//creating instance of JButton 
    b.setBounds(130,100,100, 40); 
             
    f.add(b);//adding button in JFrame 
             
    f.setSize(400,500);//400 width and 500 height 
    f.setLayout(null);//using no layout managers 
    f.setVisible(true);//making the frame visible
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    } 
     
    public static void main(String[] args) { 
    new SwingInsideConstructor(); 
    } 
    } 

Thanks
Happy programming!