Starting with a simple example, if you just want to show a JOptionPane dialog with a simple text message, all you need is one line of Java source code.
Note that when you supply a null argument like that, the JOptionPane dialog will be centered on the user's screen. When you supply a JFrame reference, the dialog is centered on that JFrame, so this behavior can be slightly different.
[
add
]
[
|
|
...
]