Once you have compiled your plugin, you will need to test its behavior when it is reloaded. Follow these steps to reload your plugin without restarting jEdit:
From the Plugins menu open the Plugin Manager.
On the Manage tab uncheck Hide libraries. This will allow you to see plugins that are not loaded.
Find the plugin on the Manage tab and uncheck it. This will unload the plugin. You will get a warning if this plugin does not support dynamic reloading. If you get that warning you will need to restart jEdit to reload the plugin until the plugin is converted over to the 4.2 API.
Recheck the plugin to reload it.
The Activator plugin provides a very convenient (dockable) way to test the activating and reloading behavior of your plugin. Be sure to test your plugin's reloading behavior with both the Activator and the Reloader tabs.
If you have reached this point in the text, you are probably serious about writing a plugin for jEdit. Good luck with your efforts, and thank you for contributing to the jEdit project.