How to center a JDialog over a JFrame in Swing

I always thought that the fact that JDialogs accepted a parent frame as a constructor argument was the thing, that would make the dialog’s position relative to that of the frame:

public JDialog(final java.awt.Frame parent, boolean modal)

Unfortunately all of my freshly opened dialogs would appear in the upper left angle of my screen, not centered over the parent JFrame. I looked around and found out that I simply needed one more method call per dialog:

theDialog.setLocationRelativeTo(theFrame);

You need to call this method before the JDialog’s show() method. Now everything is perfect and the dialog appears always right above the center of the frame.