Monitor synchronize hangs

• Testcase included:

  yes

This program (adapted from the pick-axe book) hangs in JRuby. It works without the "synchronize" block in sync_tick.

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#!/usr/bin/ruby

1. multi-threading
   require 'monitor'

class Counter
include MonitorMixin
attr_reader :count, :scount
def initialize
@count = 0
@scount = 0
super
end
def tick
@count += 1
end
def sync_tick
synchronize do
@scount += 1
end
end
end

c = Counter.new
threads = []
2.times do
threads << Thread.new { 1_000.times { c.tick; c.sync_tick }}
end

threads.each { |t| t.join }

puts "Thread counter count=#{c.count} scount=#{c.scount}"