Thread: Frame not becoming invisible

Here is a code I made to practice how to make JFrame and add components to it.
But the problem is:
1. On line 8, shouldn't the frame turn invisible?
2. On line 7, shouldn't the frame be in the center of the screen?

Could anyone help?
P.S : I did it in Ready to Program (if thats the source of any problem)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JButtonDemo2 {
        public static void main(String[] args) {
                mkay app = new mkay();
                app.setLocationRelativeTo(null);
                app.setVisible(false);
        }
}
class mkay extends javax.swing.JFrame{        
        public mkay() {
            init();
        }
        JFrame jtfMainFrame;
        JButton jbnButton1, jbnButton2;
        JTextField jtfInput;
        JPanel jplPanel;
        public void init() {
                jtfMainFrame = new JFrame("Which Button Demo");
                jtfMainFrame.setSize(50, 50);
                jbnButton1 = new JButton("Button 1");
                jbnButton2 = new JButton("Button 2");
                jtfInput = new JTextField(20);
                jplPanel = new JPanel();
                jbnButton1.addActionListener(new ActionListener() {
 
                        public void actionPerformed(ActionEvent e) {
                                jtfInput.setText("Button 1!");
                                mkay app2 = new mkay();
                                app2.setLocationRelativeTo(null);
                        }
                });
                jbnButton2.addActionListener(new ActionListener() {
 
                        public void actionPerformed(ActionEvent e) {
                                jtfInput.setText("Button 2!");
                        }
                });
                jplPanel.setLayout(new FlowLayout());
                jplPanel.add(jtfInput);
                jplPanel.add(jbnButton1);
                jplPanel.add(jbnButton2);
                jtfMainFrame.getContentPane().add(jplPanel, BorderLayout.CENTER);
                jtfMainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                jtfMainFrame.pack();
                jtfMainFrame.setVisible(true);
        }
}

What happens when you execute the program?

Try changing the setVisible parameter to true and see what happens.

The IDE should not make any difference. Your friend's code must have been different.

Did you see two windows after the change I suggested?
Look at the code. There are two JFrame objects being created.

What title is shown in the window with the components? Do a Find in the source for that String to see where it is used. Or look for a statement that has: new JFrame(

Do you now see where there are two windows being created?

Right.
One was mkay that extends JFrame

The other was:
JFrame jtfMainFrame;
...
jtfMainFrame = new JFrame("Which Button Demo");