Yesterday, I was working with generating a graph using jfreechart library. The requirement was to show a window with graph on full screen. When i used the following code it didn't give me the desired results. Taskbar was overlapping bottom part of the screen. this.setPreferredSize(new Dimension(Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit.getDefaultToolkit().getScreenSize().height)); After searching over internet i found the solution and following code snippet worked properly as per my requirements. //Calculate height of the task bar Insets scnMax = Toolkit.getDefaultToolkit().getScreenInsets(getGraphicsConfiguration()); int taskBarSize = scnMax.bottom; this.setPreferredSize(new Dimension(Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit.getDefaultToolkit().getScreenSize().height-taskBarSize)); Thanks!!!!!!!!!!!! Enjoy Programming :)