JFC stands for Java Foundation Classes. JFC are a set of Java libraries to support GUI development.
Overview of Java Foundation Classes (JFC) Features
Abstract Window Toolkit (AWT) - APIs that enable programs to integrate into the native desktop window system, including APIs for Drag and Drop.
Java 2D - APIs to enable advanced 2D graphics, imaging, text and printing.
Swing GUI Components - APIs that extend the AWT to provide a rich, extensible GUI component library with a pluggable look and feel.
Accessibility - APIs and assistive technologies are for ensuring an application is accessible to users with disabilities and meets government requirements for accessibility.
Internationalization - All JFC technologies include support for creating applications that can interact with users around the world using the user's own language and cultural conventions. This includes the Input Method Framework API.
These five technologies are designed to be used together to enable you to build fully functional GUI client applications that run and integrate on any client machine that supports the J2SE platform, including Microsoft Windows, Solaris, Linux, and Mac OSX.
Swing is, as stated above a set graphical components (implemented in Java). Swing has not only the same components as you'll find in AWT, but also new ones such as table and tree widgets.
AWT(Abstract Windowing Toolkit) was the original GUI for Java.