An explicitly class wrapped sketch for use in emacs/netbeans will run with jruby does not require k9 --run.

Methods:-

require 'jruby_art'
require 'jruby_art/app'

Processing::App::SKETCH_PATH = __FILE__

class MySketch < Processing::App
  def setup
    sketch_title 'My Sketch'
  end

  def draw
    no_loop
  end

  def settings
    size 300, 300 # or full_screen
    # pixel_density(density) # density = 2 for hi dpi display (eg retina)
    # smooth # goes here
  end
end

MySketch.new

To create such a sketch use:-

k9 --create my_sketch 300 300 # with `template: emacs` in `config.yml`