JOptionPane.showMessageDialog(null,"What does null do?");

JOptionPane.showMessageDialog(null,"What does null do?");

After much searching throught google and some java books, all I know about null is that it centers it or something and maby has something to do with this thing called frames.

Obviously this is not very helpful.

If there is someone who could show me a website or take the time to explain null and this frame thing to me, I would be very grateful

Have you read the Java API at all?
http://java.sun.com/j2se/1.4.2/docs...OptionPane.html

public static void showMessageDialog(Component parentComponent, Object message) throws HeadlessException

"The parentComponent determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used"

I would interpret this as, if you define a parentComponent, the dialog will be centered on the frame in which you define.

Specific API definition: http://java.sun.com/j2se/1.4.2/docs...va.lang.Object)