[roots]

Code:

public class Main {
	public static void main(String[] args) {
		JFrame j = new JFrame();
		j.setVisible(true);
		
		j.getContentPane().addHierarchyBoundsListener(new HierarchyBoundsListener(){

			@Override
			public void ancestorMoved(HierarchyEvent e) {
				System.out.println(e);				
			}
			@Override
			public void ancestorResized(HierarchyEvent e) {
				System.out.println(e);
				
			}			
		});
	}
}

Please run the code, you can continue thereafter ..