small medium large xlarge

Errata for Using JRuby


The latest version of the book is P1.0, released almost 5 years ago. If you've bought a PDF of the book and would like to upgrade it to this version (for free), visit your home page.

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:

If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: B8.0 (14-Dec-10)
PDF page: 38

The last paragraph on page 38 has two sentences repeated at the top of page 39.

  • Reported in: P1.0 (06-Nov-11)
PDF page: 44

url.get_protocol # Isn't assigned.

url = 'http', '', '/titles' # FIFY--Johnneylee Jack Rollins

  • Reported in: P1.0 (06-Nov-11)
PDF page: 44
attributes.rb doesn't really make sense to have a code example for, seeing as it's purely for users to digest and not actually run.--Johnneylee Jack R...more...
  • Reported in: B8.0 (05-Jan-11)
PDF page: 58
Question I had reading this: does the become_java! method described earlier help at all with the "lost monkeypatches" problem? Or does it only apply ...more...
  • Reported in: P1.0 (26-Oct-11)
PDF page: 64
Issuing the command `ant`, the `do_compile` step fails due to not finding the jruby embed package. I have issued this before running `ant`, just to...more...
  • Reported in: P1.0 (06-Nov-11)
PDF page: 68
Referring to ruby methods as functions and then again as methods is somewhat confusing. I suggest referring to ruby methods as methods and java functi...more...
  • Reported in: P1.0 (17-Feb-11)
PDF page: 83

"and long-running programs well seem" should be "and long-running programs will seem"

--Romain Primet

  • Reported in: B8.0 (18-Jan-11)
PDF page: 106
There's a much better way to do platform detection for Jruby and regular ruby You can say: platforms :jruby do gem 'activerecord-jdbc-adapter'...more...
  • Reported in: B7.0 (27-Nov-10)
PDF page: 109
I think you are aware of an issue using JRuby 1.5.5 and Rails 3.0.3 but might make mention or make sure the reader is using newer version of JRuby (fr...more...
  • Reported in: P1.0 (15-Feb-11)
PDF page: 126
When generating the scaffold for Review, the first -- argument should be --migration, not --migrate. If using --migrate, the error at the command lin...more...
  • Reported in: P1.0 (16-Feb-11)
PDF page: 155
Building Ribs using the current version of rspec (2.5.0 as it type this), as installed by the previous commands, will fail as the Rakefile assumes the...more...
  • Reported in: B8.0 (13-Jan-11)
PDF page: 169
In the first ant example the name of the target ('hello_from_ant') does not correspond with the default target name ('hello'), so calling 'ant' withou...more...
  • Reported in: B8.0 (06-Jan-11)
PDF page: 226
I have had a great deal of trouble getting JTestR to work for my project. With the config from the book (0.6) I get: [INFO] Internal error in the ...more...
  • Reported in: B7.0 (01-Dec-10)
PDF page: 243
Last line "Next install the Monkeybars gem..." would read better if it were in a new paragraph. At the moment, this gives the impression it's a netbe...more...
  • Reported in: P1.0 (02-Jul-13)
PDF page: 250
Error installing monkeybars. Book says "jruby -S gem install monkeybars rawr" but neither is found in any repository. Installed rawr like this: jr...more...
  • Reported in: P1.0 (02-Jul-13)
PDF page: 261
Command to launch limelight demos does not work: book says "jruby -S limelight open" but I haven't been able to figure out what the correct command ...more...