You'll explore Java's GUI tools in this lesson. Nearly every modern program has a graphical user interface, or GUI. That just means the program appears in a window with menus, icons, buttons, and so on. Java has hundreds of GUI tools that you can use to build your own applications to run in any windowed operating system that supports Java (Windows, Linux, and macOS, among others). You'll learn how to set up a standalone application using Java's GUI tools, including labels, buttons, dialogs, and more.