Java converts the return of Hash#select to an array when using a JRuby warbled jar

jruby-hash-array-problem.rb

#!/usr/bin/env ruby

#put this in ./bin/

#this should demonstrate that a ruby hash gets converted to an array when
#warbled

hashme = {'stringhash' => 'foo', :symbol_hash => 'sdfdf', 'nilvalue' => nil}
puts "Should be Hash: #{hashme.class.to_s}"
hashme = hashme.select {|k,v| !v.nil?}
puts "Should be Hash: #{hashme.class.to_s}"
hashme = {'stringhash' => 'foo', :symbol_hash => 'sdfdf', 'nilvalue' => nil}
hashme = hashme.reject {|k,v| v.nil?}
puts "Should be Hash: #{hashme.class.to_s}"

#this is what happens:

#[cdean@flyingbantha jruby-hash-array-problem]$ ruby bin/jruby-hash-array-problem.rb 
#Should be Hash: Hash
#Should be Hash: Hash
#Should be Hash: Hash
#[cdean@flyingbantha jruby-hash-array-problem]$ warble
#Creating jruby-hash-array-problem.jar
#[cdean@flyingbantha jruby-hash-array-problem]$ java -jar jruby-hash-array-problem.jar 
#Should be Hash: Hash
#Should be Hash: Array
#Should be Hash: Hash

warble.rb

#put this in ./config/

#note: I grep -v'd the commented lines from this for brevity
Warbler::Config.new do |config|
  config.features = %w(gemjar compiled)
  config.dirs = %w(config bin)
end