The platform is designed to accept updates and additions to the initial installation. The platform Update Manager handles this task by connecting to sites where updates are posted. (See the Workbench User Guide and Platform Installation and Update for more information about features and the Update Manager.)
You need to package your work in a form that will be accepted by the Update Manager. When you deliver an update to the platform, you are contributing a feature.
Features have a manifest that provides basic information about the feature and its content. Content may include plug-ins, fragments and any other files that are important for the feature. The delivery format for a feature is a JAR.
In PDE, your typical development process looks like this: