Here you can find the source of getFrameSize(Component c)
public static Dimension getFrameSize(Component c)
//package com.java2s; /*/*from w w w .j a v a 2 s . co m*/ * Copyright 2005 MH-Software-Entwicklung. All rights reserved. * Use is subject to license terms. */ import java.awt.Component; import java.awt.Container; import java.awt.Dimension; import java.awt.Toolkit; import java.awt.Window; import javax.swing.JInternalFrame; import javax.swing.JPopupMenu; public class Main { public static Dimension getFrameSize(Component c) { Container parent = getRootContainer(c); if (parent != null) { return parent.getSize(); } return Toolkit.getDefaultToolkit().getScreenSize(); } public static Container getRootContainer(Component c) { if (c == null) { return null; } Container parent = c.getParent(); while ((parent != null) && !(parent instanceof JPopupMenu) && !(parent instanceof JInternalFrame) && !(parent instanceof Window) && (parent.getParent() != null)) { parent = parent.getParent(); } return parent; } }