To use Groovy from inside jEdit download this plugin. You'll need a fairly recent jEdit distribution.
Right now BSF isn't yet released with inbuilt Groovy support so you have to add the following code to the startup script in
You can also add a startup.bsh script into your home directory at
Also you'll need to copy the groovy*.jar and asm*.jar files into the jedit/jars directory.
Open SuperScript dockable from Plugins Menu or Dockable area and choose "groovy" from the languages dropdown.
To test if groovy works fine or not, just try running some expression in the textbox or open some groovy script in jEdit and try "Executing Script".