Close one JFrame without closing another?

I want to display two (or more) JFrames at the same time.
When I close one of them (use the default close button), the other frames should still be visible.

How can I do that?

If you do not want your application to terminate when a JFrame is closed, use

setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE)

instead of

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

From the documentation:

• DO_NOTHING_ON_CLOSE (defined in WindowConstants): Don't do anything; require the program to handle the operation in the windowClosing method of a registered WindowListener object.
• HIDE_ON_CLOSE (defined in WindowConstants): Automatically hide the frame after invoking any registered WindowListener objects.
• DISPOSE_ON_CLOSE (defined in WindowConstants): Automatically hide and dispose the frame after invoking any registered WindowListener objects.
• EXIT_ON_CLOSE (defined in JFrame): Exit the application using the System exit method. Use this only in applications.

---

This was my answer before the question was clarified, might still be useful:

You can use setVisible(false) on your JFrame if you want to display the same frame again.
Otherwise call dispose() to remove all of the native screen resources.

Does it help you ?

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TwoJFrames {
	public static void main(String[] args) {
		int nb = 4;
		if (args != null && args.length > 0) {
			nb = Integer.parseInt(args[0]);
		}
		
		final int frameCount = nb;
		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				for (int i = 0; i < frameCount; i++) {
					JFrame frame = new JFrame("Frame number " + i);
					frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
					JPanel p = new JPanel(new BorderLayout());
					p.add(new JLabel("Click on the corner to close..."), BorderLayout.CENTER);
					frame.setContentPane(p);
					frame.setSize(200, 200);
					frame.setLocation(100 + 20 * i, 100 + 20 * i);
					frame.setVisible(true);
				}
			}
		});

	}
}