Java Foundation Classes (JFC) is a set of Application Programming Interfaces (APIs) that provide a framework for developing GUI-based applications in Java programming language. JFC includes several components, such as Swing for building cross-platform graphical user interfaces and Abstract Window Toolkit (AWT) for providing a platform-specific interface. JFC is widely used for developing desktop applications, web applications, and games. Mastery of JFC requires strong knowledge of Java programming basics, including inheritance, polymorphism, and event handling.