Java Swing Text Editor

Creating my first program in Swing and I was hoping to get some feedback. I'm looking for constructive criticism and tips for my swing code and my code in general. Don't really know what I'm doing so any advice would be helpful. The program is a simple text editor like notepad. Everything works the way I want it to so far but I'd like to know if I'm doing something wrong or if I could do something better.

```
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.*;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;

public class test2 extends JFrame implements ActionListener, ComponentListener, MouseListener {
JMenuBar menuBar;
JPanel textPanel;

public test2() {
//set up the Frame
setTitle("Simple Text Editor");
setLayout(null);
setSize(1280, 720);
setDefaultCloseOperation(EXIT_ON_CLOSE);
UIManager.put("Menu.selectionBackground", Color.LIGHT_GRAY);

//create the menu bar
menuBar = new JMenuBar();
menuBar.setBounds(0, 0, getWidth(), 25);
menuBar.setBackground(Color.WHITE);
menuBar.setFont(new Font("Arial", Font.PLAIN, 14));
add(menuBar);

//create the menus
JMenu fileMenu = new JMenu(" File ");
JMenu editMenu = new JMenu(" Edit ");
JMenu formatMenu = new JMenu(" Format ");
JMenu helpMenu = new JMenu(" Help ");
fileMenu.setFont(new Font("Arial", Font.PLAIN, 14));
editMenu.setFont(new Font("Arial", Font.PLAIN, 14));
formatMenu.setFont(new Font("Arial", Font.PLAIN, 14));
helpMenu.setFont(new Font("Arial", Font.PLAIN, 14));
menuBar.add(fileMenu);
menuBar.add(editMenu);
menuBar.a

Violating important threading practices

test2 a = new test2();

The swing documentation state all swing actions should be done from the event dispatch thread. If these rules are broken, weird bugs can occur with your application.

The documentation states:


Swing event handling code runs on a special thread known as the event
dispatch thread. Most code that invokes Swing methods also runs on
this thread. This is necessary because most Swing object methods are
not "thread safe": invoking them from multiple threads risks thread
interference or memory consistency errors. Some Swing component
methods are labelled "thread safe" in the API specification; these can
be safely invoked from any thread. All other Swing component methods
must be invoked from the event dispatch thread. Programs that ignore
this rule may function correctly most of the time, but are subject to
unpredictable errors that are difficult to reproduce.

Wrap the call in a SwingUtilities.invokeLater call:

SwingUtilities.invokeLater(new Runnable(){
    @Override
    public void run() {
        test2 a = new test2();
    }
});

Creating to much new font objects

menuBar.setFont(new Font("Arial", Font.PLAIN, 14));
    fileMenu.setFont(new Font("Arial", Font.PLAIN, 14));
    editMenu.setFont(new Font("Arial", Font.PLAIN, 14));
    formatMenu.setFont(new Font("Arial", Font.PLAIN, 14));
    helpMenu.setFont(new Font("Arial", Font.PLAIN, 14));
    Font font = new Font("Helventica", Font.PLAIN, 14);

If you ever wanted to change the font size or change the font type, you must change at least 6 different lines. While this amount doesn't look like much, all these lines are spread throughout the program making it a mess.

By placing these fonts as constants at the top of your class, you can get a cleaner code.

private static final Font MENU_FONT = new Font("Helventica", Font.PLAIN, 14);
private static final Font BODY_FONT = new Font("Arial", Font.PLAIN, 14);

Then do:

helpMenu.setFont(BODY_FONT);

Delegate the setVisible call to the object creator

By delegating the call to the method that creates the gui, it allows the other class to modify things in the gui before its being displayed, this will enable a variety of useful features.

test2 a = new test2();
a.setVisible(true);

StackExchange Code Review Q#119572, answer score: 6