Whilst playing around with NetBeans 6.5 and JRuby on my shiny new openSUSE 11.1 installation, I decided to create a new Rails project. It's been quite a while since I last played with Ruby on Rails, so I decided to start from scratch. One of the choices I made in the new project's creation was the selection of JavaDB (a.k.a. Derby) as the database. I also choose to use JRuby 1.1.6, which was released 17 December, instead of the built-in NetBeans version, 1.1.4. JRuby 1.1.6 is installed external to the NetBean's installation location. While attempting to run (for the first time) the project, it stopped with an error in the output window (see below).
The error was that it could not establish a connection with Derby and that I needed to install the Derby adapter gem; 'gem install activerecord-derby-adapter'. The problem is there is no gem with that name. Instead you need to type 'gem install activerecord-jdbcderby-adapter'. There is a reporting bug within connection_specification.rb, which is a part of Ruby's gems (lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/connection_specification.rb).
Once properly installed the Rails project started up just fine. I also need to point out that if you use an external JRuby installation you'll need to install rails (gem install rails). I know, you can pass along command line switches to disable the installation of documentation, but does it really take that long to download and install the documentation?