jruby_selector_leak.rb

num_runtimes = 10

puts "Creating runtimes..."
num_runtimes.times do
  instance = org.jruby.Ruby.newInstance
  instance.evalScriptlet <<-EOS
    require "socket"
    server = TCPServer.new(0)
    Thread.new do
      begin
        server.accept
      rescue Exception => ex
      end
    end
    Thread.new do
      sleep 1
      JRuby.runtime.tearDown(false)
    end
  EOS
end

puts "Waiting for runtimes to teardown..."
sleep 5

mbean = java.lang.management.ManagementFactory.getThreadMXBean
threads = mbean.getThreadInfo(mbean.getAllThreadIds)
thread_names = threads.map(&:thread_name)

leaked_runtimes = thread_names.select do |name|
  name =~ /Ruby-\d+-Thread-\d+/
end

puts "Created #{num_runtimes} JRuby runtimes and #{leaked_runtimes.size} " +
  "leaked waiting on a selector"

exit 1 if leaked_runtimes.size > 0

output.txt

# JRuby 1.7.21
$ jruby jruby_selector_leak.rb 
Creating runtimes...
Waiting for runtimes to teardown...
Created 10 JRuby runtimes and 10 leaked waiting on a selector

# JRuby 9.0.0.0
$ jruby jruby_selector_leak.rb 
Creating runtimes...
Waiting for runtimes to teardown...
Created 10 JRuby runtimes and 10 leaked waiting on a selector

# JRuby 9.0.1.0-SNAPSHOT + selector leak patch
$ jruby jruby_selector_leak.rb 
Creating runtimes...
Waiting for runtimes to teardown...
Created 10 JRuby runtimes and 0 leaked waiting on a selector