“1.3 Preparing Twitalytics for JRuby” (7)
The text assumes that jruby-lint-0.3.1 will be the version installed, or at least that a later version installed will produce the same output. jruby-lint-0.4.1 outputs “Found 12 items”, not “Found 4 items”. The additional items are all warnings relating to non-atomic operations such as “a += b” or “a = b”. Changing the Ruby source to “a = a + b” and “a = a b” for the lines reported as being problematic will get jrlint back to producing the “Found 4 items” which the text expects. Alternatively, the text should instruct the reader to use
$ gem install jruby-lint Successfully installed jruby-lint-0.3.1 1 gem installed $ jrlint
$ gem install jruby-lint -v "0.3.1"
to get the exact version with known behaviour.