AWT: The idea was to wrap the native GUI widgets of the various operating systems with a platform-independent Java API called Abstract Window Toolkit (AWT). Only common widgets such as text field, text area, check box, radio button, list, and push button were supported by AWT. The graphics and imaging features were also very limited. That was, at best, enough for building simple applets.
SWING: is one of the most complex GUI frameworks ever developed. It has a complete set of GUI components ranging from buttons and text fields to tables, trees, and styled text editors. These components do not rely on the native widgets of the operating system; instead, Swing components are painted using graphic primitives such as lines, rectangles, and text. The painting is delegated to a look and feel (L&F) plug-in that can imitate the native L&F. Swing also has a platform-independent L&F called "Metal." JBuilder, uses Swing, and its speed is quite good.
Standard Widget Toolkit (SWT) is the GUI toolkit developed by IBM for its Eclipse IDE. SWT can be used outside of the Eclipse environment and offers direct access to the native GUI features of the operating system. Therefore, SWT-based Java applications have native GUIs and can be integrated with other native applications and components. SWT delegates to native widgets for common components (such as labels, lists, tables, and so on) as AWT does, while emulating in Java more sophisticated components (for example, toolbars are emulated when running on Motif) similarly to Swing's strategy.SWT has been designed to be as inexpensive as possible. This means (among the other things) that it is native-oriented. Anyway, it differs from AWT in a number of details. SWT provides different Java implementations for each platform, and each of these implementations calls natively (through the Java Native Interface, JNI) the underlying native implementation. The old AWT is different in that all platform-dependent details are hidden in C (native) code and the Java implementation is the same for all the platforms.