Java tutorial
//package com.java2s; import java.awt.Component; import java.awt.Container; import java.awt.Dimension; public class Main { public static void padPreferredWidthDeep(Component component, int padding) { if (component instanceof Container) { for (Component child : ((Container) component).getComponents()) { padPreferredWidthDeep(child, padding); } } component.setPreferredSize(new Dimension((int) component.getPreferredSize().getWidth() + padding, (int) component.getPreferredSize().getHeight())); } }