import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JRootPane;
import javax.swing.SwingUtilities;

public class JFrameWithNoMinMax extends JFrame {

  public JFrameWithNoMinMax() {
      createAndShowUI();
  }

  private void createAndShowUI(){
    setTitle("This JFRAME looks like JDialog");
    setSize(new Dimension(500,100));
    setUndecorated(true);
    setResizable(false);
    getRootPane().setWindowDecorationStyle(JRootPane.PLAIN_DIALOG);
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    //addWindowListener(new WindowAdapter(){
    //  public void windowClosing(WindowEvent e) {
    //    System.out.println("Window Closing");
    //    System.exit(0);
    //  }
    //});
  }

  public static void main(String[] args){
    SwingUtilities.invokeLater(new Runnable(){
       public void run(){
         new JFrameWithNoMinMax().setVisible(true);
       }
    });
  }
}