jruby-head :001 > RUBY_VERSION
 => "1.9.3" 
jruby-head :002 > require 'set'
 => true 
jruby-head :003 > s=Set.new [129]
 => #<Set: {129}> 
jruby-head :004 > s2=Set.new( s.to_a.pack('w*').unpack('w*') )
 => #<Set: {129}> 
jruby-head :005 > s.to_a==s2.to_a
 => true 
jruby-head :006 > s==s2
 => false