The online archive of Eclipse articles contains more than 50 articles written by the Eclipse experts, often the committers of the Eclipse projects described in the articles. When printed in sequence, the online articles contain more than 500 pages of deep knowledge of the Eclipse Platform.
The audience for the online articles is extenders of the platform, so it makes a lot of sense to consult the articles before trying to write your own Standard Widget Toolkit (SWT) widget, implement a preference page, react to workspace resource change events, launch an application from Eclipse, support drag-and-drop, use Draw2D, internationalize your plug-in, turn your plug-in collection into a product, write an editor for your favorite programming language and integrate it into Eclipse, use a tree viewer, use decorators and markers, or create CVS branches in your team project.
In addition to the online Eclipse articles, a wealth of Eclipse experience is reported on the IBM developerWorks Web site, with many articles and code samples.