Since there seems to be some argument about what constitutes "best practices", I'll give you what I have found works best for me, and my reasoning:
1.
Each window should extend either JFrame or JDialog (depending on the type of window). This makes it easy to control the properties of the window without specifying a specific object every time. This is more of the general case, though, as I have been known to do it both ways.
2.
The main() method should be in a separate class. This increases the likelihood of being able to use your window classes elsewhere, as they are not tied to specific implementations. Technically it doesn't make a difference, but application startup code just doesn't belong in a window.
3.
Listeners should be in anonymous inner classes. Your top-level class should not implement any listeners. This prevents hacks like calling the listener methods from anywhere except the object to which they are attached.
Here is a simple application with a single frame to demonstrate these practices:
public class Main {
public static void main(String[] args) {
final String text = args[0];
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
final MyWindow wnd = new MyWindow(text);
wnd.setVisible(true);
}
});
}
}
public class MyWindow extends JFrame {
public MyWindow(String text) {
super("My Window");
setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
MyWindow.this.setVisible(false);
MyWindow.this.dispose();
}
});
final JButton btn = new JButton(text);
btn.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(MyWindow.this, "Button Pressed", "Hey", JOptionPane.INFORMATION_MESSAGE);
}
});
setLayout(new FlowLayout());
add(btn);
pack();
}
}
