import javax.swing.*;
import java.awt.event.*;
public class MyFrame extends JFrame {
public MyFrame(String title) {
super(title);
setSize(400, 300);
setResizable(false);
setLocationRelativeTo(null);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
addWindowStateListener(new WindowStateListener() {
public void windowStateChanged(WindowEvent e) {
if(e.getNewState() != JFrame.NORMAL) {
MyFrame.this.setExtendedState(JFrame.NORMAL);
}
}
});
}
public static void main(String[] args) {
new MyFrame("MyFrame").setVisible(true);
}
}