• Ruby: parallel processing made simple and fast
• http://morizyun.github.io/blog/parallel-process-ruby-gem/
• http://www.hyuki.com/yukiwiki/wiki.cgi?WhatThreadsafeRailsMeans

java

ConcurrentHashMap

HashMap, HashTable, ConcurrentHashMapに比較

• http://software.fujitsu.com/jp/technical/interstage/apserver/guide/pdf/concurrenthashmap-20120105.pdf
• HashMap - thread not safe
• HashTable - thread safe. but slow
  • 使わない
• ConcurrentHashMap - thread safe. fast