Here you can find the source of fullScreen(Component component)
public static final void fullScreen(Component component)
//package com.java2s; import java.awt.Component; import java.awt.Dimension; import java.awt.Frame; import java.awt.Toolkit; public class Main { public static final void fullScreen(Component component) { Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); Dimension frameSize = component.getSize(); if (frameSize.height > screenSize.height) { frameSize.height = screenSize.height; }/*from w ww . java 2s . co m*/ if (frameSize.width > screenSize.width) { frameSize.width = screenSize.width; } component.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2); } public static final void fullScreen(Frame frame) { frame.setExtendedState(Frame.MAXIMIZED_BOTH); } }