Modular Java – Creating Flexible Applications with OSGi and Spring, Craig Walls, Pragmatic, 2009
Java programmers will want to read this, particularly if they are working with Eclipse plugins. OSGi is an improvement on Java’s classes and packages. The Pragmatic people explain it all so well. 240 pages.
The definitive guide to SWT and JFace / Rob Warner with Robert Harris. Apress Springer Verlag, c2004.
Here is a good introduction to Eclipse GUI programming. Though somewhat dated, it is still worth reading. It will help if you are doing a Rich Client (RCP) or extending Eclipse with a new plugin. SWT is way better than Swing, but there seem to be fewer books on it. There is a lot to learn, and too many sources on the net, so use this book to get started.
Eclipse : building commercial-quality plug-ins / Eric Clayberg, Dan Rubel ; Addison-Wesley, c2004.
If you are extending Eclipse or designing a Rich Client (RCP) then this book will be useful. Also if you are planning a Java project, and want to see a project architecture.
It is dated now (2008), but the main concepts have not changed.
Official Eclipse 3.0 FAQs / John Arthorne, Chris Laffra. Addison-Wesley, 2004
Eclipse is a big system, and there is a lot to be learned about it. This book is somewhat dated, but you will want to read it if you are using or extending Eclipse.