Each subclass of class Screen is a complete functional user interface element. The software in a given MIDP device implements each kind of Screen using the native look and feel of the device. The device software takes care of all events that occur as the user navigates in a Screen. When a user action causes a Command invocation event, the event is passed to the application, which brings about a transition to a different Screen. Each Screen can have a title, multiple Commands, and a Ticker. It is up to the device software to include these elements in the visual presentation of the Screen. The four kinds of Screens (List, TextBox, Alert, and Form) are described in this chapter.