Java: JOptionPane showMessageDialog examples (part 1)

By Alvin Alexander. Last updated: April 6, 2024

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I’ve been working with the Java JOptionPane showMessageDialog a lot lately, so I thought I’d create a page here with a number of showMessageDialog examples, sort of a JOptionPane reference page.

I’ll walk you through some Java JOptionPane examples here, starting with a simple example and then increasing the level of difficulty as I go on.

A simple JOptionPane example

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, like this:

JOptionPane.showMessageDialog(frame, "A basic JOptionPane message dialog");

When this line of code is executed it will display the following message dialog:

JOptionPane showMessageDialog - simple example

In that example my first argument to the JOptionPane showMessageDialog method is a frame object, which presumably is an instance of a JFrame. If for some reason you don't have a reference to JFrame or JWindow instance, you can make that field null, and still display the identical JOptionPane dialog, as shown in this example:

JOptionPane.showMessageDialog(null, "A basic JOptionPane message dialog");

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.

A complete example

Now looking at this as a more complete showMessageDialog example, here is the source code for a complete Java class that demonstrates a showMessageDialog example with a slightly more complex message:

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class ShowMessageDialogExample1
{
  public static void main(String[] args)
  {
    String backupDir = "/Users/al/backups";
    
    // create a jframe
    JFrame frame = new JFrame("JOptionPane showMessageDialog example");
    
    // show a joptionpane dialog using showMessageDialog
    JOptionPane.showMessageDialog(frame,
        "Problem writing to backup directory: '" + backupDir + "'.");
    System.exit(0);
  }
}

JOptionPane showMessageDialog - example with no title

JOptionPane dialog: A custom title

Taking this JOptionPane showMessageDialog example to the next level, in a real world application you want to display your message dialog with a title, so next I’ll add a title to the showMessageDialog method. However, adding a title also forces me to add a message type when I call the showMessageDialog method (as you'll see from the general syntax options available, shown later), so in this JOptionPane example I’ll choose the INFORMATION_MESSAGE type:

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class ShowMessageDialogExample1
{
  public static void main(String[] args)
  {
    String backupDir = "/Users/al/backups";
    
    // create a jframe
    JFrame frame = new JFrame("JOptionPane showMessageDialog example");

    // show a joptionpane dialog using showMessageDialog
    JOptionPane.showMessageDialog(frame,
        "Problem writing to backup directory: '" + backupDir + "'.",
        "Backup problem",
        JOptionPane.INFORMATION_MESSAGE);
    System.exit(0);
  }
}

This results in the following message dialog:

JOptionPane showMessageDialog - custom title example

As you can see, this JOptionPane message dialog now includes a title, and also includes a new icon that wasn’t there before. This icon comes from the addition of the INFORMATION_MESSAGE argument to the showMessageDialog method.

JOptionPane with error message icon

I won’t repeat all that Java source code here, but if you repeat the exact same example, and replace the INFORMATION_MESSAGE type with an ERROR_MESSAGE type, like this: