The applications in Chapters 210 display text at the command window and obtain input from the command window. Most applications you use on a daily basis use windows or dialog boxes (also called dialogs) to interact with the user. For example, e-mail programs allow you to type and read messages in a window provided by the e-mail program. Typically, dialog boxes are windows in which programs display important messages to the user or obtain information from the user. Java s JOptionPane class (package javax.swing) provides prepackaged dialog boxes for both input and output. These dialogs are displayed by invoking static JOptionPane methods. Figure 11.2 presents a simple addition application that uses two input dialogs to obtain integers from the user and a message dialog to display the sum of the integers the user enters.