Here is an example from an older version of Active Support that I still use:
On the very last line of active_support/inflector.rb, there is a line that uses the _FILE_ reference:
require File.dirname(__FILE__) + '/inflections'
Which is translated to "./active_support/inflections" at run time. However, if /active_support/inflections.rb has been pre-compiled as a Java class, then you have to load it with the name "active_support/inflections" and not "./active_support/inflections" Otherwise, even if active_support/inflections.class is available, the following error result:
no such file to load -- ./active_support/inflections
The attached patch only changes the very specific case of locating a Java class, and it does not affect other cases, such as loading .rb files or any other such ways.