gistfile1.txt

require 'singleton'

loop do
  classes = []
  1000.times do
    classes << Class.new do
      include Singleton
    end
  end

  (0..10).map do
    Thread.new do
      classes.each do |cls|
        cls.instance
      end
    end
  end.map(&:join)
  puts "loop completed"
end

% ruby -v singleton_killer.rb
ruby 1.8.7 (2010-08-16 patchlevel 302) [i686-darwin10.4.0]
loop completed
loop completed
loop completed
loop completed
loop completed
loop completed
loop completed
loop completed
loop completed
singleton_killer.rb:18: undefined method `instance' for #<Class:0x1001896a0> (NoMethodError)
       from singleton_killer.rb:1:in `join'
       from singleton_killer.rb:1:in `to_proc'
       from singleton_killer.rb:21:in `map'
       from singleton_killer.rb:21
       from singleton_killer.rb:5:in `loop'
       from singleton_killer.rb:5


% ruby -v singleton_killer.rb
ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]
loop completed
loop completed
loop completed
loop completed
singleton_killer.rb:18: undefined method `instance' for #<Class:0x100348c70> (NoMethodError)
       from singleton_killer.rb:1:in `join'
       from singleton_killer.rb:1:in `to_proc'
       from singleton_killer.rb:21:in `map'
       from singleton_killer.rb:21
       from singleton_killer.rb:5:in `loop'
       from singleton_killer.rb:5