AWT (Abstract Window Toolkit) is a set of classes in the Java programming language that provides the foundation for building graphical user interfaces (GUIs). It was the first GUI toolkit for Java and is part of the Java Foundation Classes (JFC).

AWT includes a set of components like buttons, checkboxes, radio buttons, labels, lists, text fields, and other graphical elements that are used to create user interfaces for desktop applications. These components are implemented using native platform-specific code for the platform on which the application is running.

AWT is platform-dependent, which means that the look and feel of AWT components may vary depending on the platform. For example, a button on a Windows platform may look different from a button on a Mac platform. This can be an advantage, as it allows the user interface to better match the platform's native look and feel, but it can also be a disadvantage, as it can make it harder to create a consistent user interface across multiple platforms.

Despite its advantages and disadvantages, AWT is still widely used today, particularly in legacy applications. However, for new applications, most developers tend to use Swing or JavaFX, which are newer and more feature-rich GUI toolkits that were built on top of AWT.