Eclipse is a successful implementation of various kinds of design patterns and Java technologies. It has layered structure and those components in different layer finally forms a powerful platform which can be used for developing high-performance, stable and flexible applications. To decipher the secrets and designs behind Eclipse, the articles under Architecture category explore the eclipse platform architecture and the design patterns used for each component. Once you understand the Eclipse design, you can quickly learn how to program according to its rules. And more importantly, those design ideas can be used for your future Java development.
The articles under Rich Client Platform(RCP) category describe how to write an Eclipse plug-in or a rich client application. They normally are read working code with screenshots.
If you are interested in processing Java code, Eclipse JDT would be your best friend. Under Java Development Tools (JDT) category, you can find code required to explore workspace and parse Java projects.