The Eclipse Project aims to create, as themselves define, “a kind of universal tool
platform - an open extensible IDE for
anything and nothing in particular”. The most known aspect of the project is the Java IDE, but it's not only about it. You'll find there a great infrastructure for building several kinds of tools and frameworks for software development.
Eclipse is an open-source, royalty-free, vendor-neutral and multi-
platform project. However one of its most noteworthy
features is the plugin-based architecture. This has allowed a great number of IDE extensions to become available, both proprietary and open-source, which has definitely contributed to its great success in the community. There's extensions for everything imaginable. Think about your preferred language, try googling for 'language eclipse plugin' and it's likely that you'll find something. Otherwise you just can develop your own. Eclipse's ecosystem provides a huge base of technologies for software development.
Eclipse Platform The core project developed by the Eclipse.org community is the Eclipse Platform, which is the basis for building any other tools, such as the Java IDE. It provides the core runtime upon which all the other components (plug-ins) run, and also all the generic and language-independent features used by them. Eclipse Platform consists in the Runtime, Workspace, Workbench and some frameworks.
The Platform Runtime is the core engine upon which all the other components run, just dealing with plug-in management. The Workspace manages directories and files, and the Workbench is the core of the user interface, defining basic UI entities (perspectives, views and editors) and also being the GUI for the Workspace.
The frameworks in the Platform are Help, for documentation, Team for version control and resource change history, Debug for general debugging and Update for automatic updates.
Eclipse JDT The Java Development Tools project provides the functionality of a Java IDE. It extends the Eclipse Platform to enable Java source code editing, compiling and debugging, and adds Java-specific UI elements in the IDE such as the Java perspective. It's the basis for every plug-in related to Java functionality.
Eclipse SDK The Eclipse SDK is the standard distribution package for the Eclipse's Java IDE. It contains JDT and PDE, enabling also plug-in development features on the development environment.
Eclipse WTP The Web Tools Platform complements the standard Java IDE (JDT) with features for building web and J2EE applications. The Web Standard Tools (
WST) provide editing of web resources such as HTML, CSS, JavaScript, XML, DTD and XSD. It's not specific to Java and thus can be used for web tasks in general. The J2EE Standard Tools (
JST) extend WST to support J2EE development aspects such as JSPs, EJBs and Web Services.
The JDT compiler Eclipse.org has developed its own Java compiler which has several advantages over the official one provided in the JDK. It's much faster and has much more warnings than javac, beyond being open-source, which means that you don't need JDK to deploy a Java compiler. Besides the compilation is incremental, that is, as you type code only its modified lines are recompiled, and partial, which means that you can compile code even with errors (generating exceptions if executed).
This compiler is considered as a good alternative for the standard javac if you need to include compilation features into your project for its more flexible licensing and noteworthy quality.
Go ahead! This isn't just what Eclipse is. You'll find still several other projects in the Eclipse.org website. It wasn't mentioned here for example projects for report generation (BIRT), visual GUI development (VE), AOP and C/C++ programming (AJDT, CDT), and more. Outside of the website you'llher languages and development tasks. PHP, Python, Ruby, Fortran, databases, modeling, testing, performance. All these have plug-ins somewhere in the web, you just have to find them.
Well, I hope this little talk we've had gives you at least some idea of what's Eclipse all about, and also serves as an encouragement to try it and see how this wonderful tool can make software development a more enjoyable experience.