How can I determine all of the components contained in a JFrame?

To get a list of all components in a JFrame, you could need to write a recursive method like the following:

public void getAllComponents(Component c, Collection collection) {
  collection.add(c);
  if (c instanceof Container) {
    Component[] kids = ((Container)c).getComponents();
    for(int i=0; i<kids.length; i++)
      getAllComponents(kids[i], collection);
  }
}

You would then pass in any collection you want to the method.

If you wanted to perform a different action on each component, you could replace the "collection.add(c)" call with whatever code you wish.

  component.getTopLevelAncestor();

  SwingUtilities.getWindowAncestor(comp);

(Note that SwingUtilities doesn't require the GUI be written in Swing...)