Swing/AWT/SWT :: How To Prompt Before Exit In Single Frame Application

I have a Single Frame Application and I simply want to prompt the user with a dialog confirming they really want to close before they actually close the program, specifically when they click the X in the upper right. I THOUGHT it was like any other java application, with the slight added complexity of having to target the program-created-JFrame with: ".getApplication().getMainFrame()".

MyApp.getApplication().getMainFrame().setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

With that code, DO_NOTHING_ON_CLOSE is set on the JFrame, yet the program closes anyways. Which I don't understand.So I did some reading and found this: URL....That lead me to the configureWindow override, where I successfully tried this:

root.addWindowListener(new WindowAdapter() {

@Override
public void windowClosing(WindowEvent e) {
// write your code here
System.out.println("Window Closing");
}
});

But as far as I can tell that will only let me react to the window closing, not to the command to close it, where I could then kill the command in the dialog if they so "no I'm not ready to quit yet", if that makes sense. So, how to give a prompt before closing?I am using netbeans IDE to create this app - not sure if that is relevant, since maybe it is an oddity with the IDE and not Single Frame Applications.