Thread: JDialogs

I am a complete newbie in making GUI in Java Swing and Java in general. I am use to using Qt, so any harsh comments and feedback will be taken lightly, so don't worry about my naive questions. It took me a while to make a Dialog with just using JPanel and JFrame, but my problem is when I execute the program two dialogs pop-up. One with the right display and one that is completely blank and small.

If someone can tell me what I am doing wrong I would greatly appreciate it.

Here is the code. OH ALSO comment on how to properly post code as well.

Thanks

package com.familydatabasetest.domain;
 
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
 
 
 
public class MainForm extends JDialog{
 
    private final JTable nameTable;
    private JScrollPane nameScroll;
    private final JTable infoTable;
    private JScrollPane infoScroll;
 
    private JPanel mainPanel;
    private JPanel buttonPanel;
 
    private JButton addNameButton;
    private JButton deleteNameButton;
    private JButton editButton;
 
    public MainForm(){
 
        final JFrame frame = new JFrame("Family Database");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 500);
 
        nameTable = new JTable();
        nameTable.setPreferredScrollableViewportSize(new Dimension(100, 200));
        nameTable.setFillsViewportHeight(true);
        nameScroll = new JScrollPane(nameTable);
        infoTable = new JTable();
        infoTable.setPreferredScrollableViewportSize(new Dimension(100, 200));
        infoTable.setFillsViewportHeight(true);
        infoScroll = new JScrollPane(infoTable);
 
        addNameButton = new JButton("Add Name");
        addNameButton.setPreferredSize(new Dimension(50, 5));
        addNameButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                NameForm nameform = new NameForm();
                nameform.show();
            }
        });
        deleteNameButton = new JButton("Delete Name");
        deleteNameButton.setPreferredSize(new Dimension(50, 5));
        editButton = new JButton("Edit");
        editButton.setPreferredSize(new Dimension(50, 5));
 
        mainPanel = new JPanel();
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
        buttonPanel = new JPanel(new GridLayout(1, 3));
 
        buttonPanel.add(addNameButton);
        buttonPanel.add(deleteNameButton);
        buttonPanel.add(editButton);
 
        mainPanel.add(nameScroll);
        mainPanel.add(infoScroll);
        mainPanel.add(buttonPanel);
 
        frame.setContentPane(mainPanel);
        frame.setVisible(true);
 
    }
}
 
//Here is the main
package familydatabasetest;
 
import com.familydatabasetest.domain.MainForm;
 
 
public class FamilyDatabaseTest {
 
 
    public static void main(String[] args) {
 
 
        MainForm mainform = new MainForm();
        mainform.show();
 
 
    }   
}

//Keep in mind I am use to using C++/QT
//Thanks

Sorry for the late delay I had trouble with my screen. Anyways, what's wrong with pubic class MainForm extends JDialog. I got that from a tutorial. Do I have to call its constructor??

Please explain with more detail so.