The Plug-in Development Environment (PDE) is a tool that is designed to help you develop platform plug-ins while working inside the platform workbench.
PDE provides a set of platform extension contributions (views, editors, perspectives, etc.) that collectively streamline the process of developing plug-ins inside the workbench.
In line with the general platform philosophy, PDE is not a separately launched tool. When you install PDE, your workbench will look the same, but you will see that new perspectives, wizards, editors, and views are available. PDE blends with the platform and offers its capabilities through a new perspective.
PDE is based on the platform and the Java development tooling (JDT). You need to understand the concepts presented in the Platform ISV Guide and the JDT User Guide in order to use PDE and understand the remaining concepts in this guide.