#Java base class
public abstract class BaseTest
{
  public BaseTest()
  {
  }
}

#Ruby subclass
require 'java'

include_class 'BaseTest'

class Foo < BaseTest
  def initialize

  end

  def setup
    puts "in setup"
  end
end

f = Foo.new
f.setup

#/Users/dkoontz/dev/libs/jruby/jruby/src/builtin/javasupport.rb:311:in `setup_instance_methods': unable to
#create proxy class for class BaseTest (ArgumentError)
#        from /Users/dkoontz/dev/libs/jruby/jruby/src/builtin/javasupport.rb:311:in `inherited'
#        from basetest.rb:14