Hi Tee,
You might miss
this thread and there you can see the following main concept of SWT and JFace by Mr.Rob...
In a nutshell, SWT is a widget toolkit (buttons, menus, tables, trees, et al.), that uses native widgets to ensure precise desktop integration and best performance. JFace is an abstraction layer that rides on top of SWT--sort of an MVC layer. You can use SWT without using JFace, but in many cases JFace makes development easier.
Hope it helps...
Co-author of SCMAD Exam Guide, Author of JMADPlus
SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0