CVS Howto - Eclipsepedia - Guide to start develop new plugins for eclipse

There are several ways to get the source for the Eclipse projects. Most developers are actually developing their own plug-ins and are interested in browsing the Eclipse source and using it during debugging. For this, you can either browse the CVS repository online or use the source included in the Eclipse SDK download. The download contains source zips which can be attached to jars in the SDK's Java tooling and used for browsing and debugging.

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CVS Howto - Eclipsepedia: "CVS Howto"

This is nice guide to start develop new plugins for eclipse