This Java source code defines a simple mouse tracking program using Swing which is a graphical user interface toolkit. The program displays a window with a drawing surface that captures and visualizes various mouse events.

The mouse’s current coordinates, modifier keys (Shift, Control, Meta, and Alt), and the type of the most recent mouse event are displayed in real-time on the window.

The code is organized into a main class, SimpleTrackMouse, and a nested class, Display, which handles the drawing surface. Key concepts covered in the code include event handling through interfaces (MouseListener and MouseMotionListener), drawing on a panel and updating graphical components dynamically. Additionally, it introduces the use of Swing’s JPanel for GUI components.

For a novice Java programmer, this code provides a practical example of basic GUI development and event handling, offering a foundation for understanding more complex Java applications in the future.