The following will create a plugin which will contribute a menu entry to the standard Eclipse menu. Create a plugin project "de.vogella.plugin.first" via File -> New -> Project -> "Plug-in Development" -> "Plug-in Project".

Select the "Hello, World Command!" template and press Finish. This should automatically open the "Plug-in Development perspective".

Select the file "MANIFEST.MF", right click it, select Run-As-> Eclipse Application

A new workbench starts with a new menu entry. If you select this menu entry a message box will be displayed.