gistfile1.txt

one.rb -------------------------------------
$GLOBAL = "ONE"

class Foo
  def global
    return "#{__FILE__}:GLOBAL = #{$GLOBAL}"
  end
end

foo = Foo.new
puts "foo.global: #{foo.global}"
Java::Main.thing = foo

two.rb --------------------------------------
puts "$GLOBAL: #{$GLOBAL}"

$GLOBAL = "TWO"

thing = Java::Main.thing
puts "thing: #{thing}"
puts "thing.global: #{thing.global}"

output --------------------------------------
foo.global: ruby1:GLOBAL = ONE
$GLOBAL: 
thing: #<Foo:0x1b4b74a7>
thing.global: ruby1:GLOBAL = TWO