The IBM_DB Ruby driver and Rails adapter are not supported on JRuby

The IBM_DB adapter is not supported on JRuby.

The IBM_DB adapter is not supported on JRuby because (as stated in the JRuby Wiki, "Getting Started"): "Many Gems will work fine in JRuby, however some Gems build native C libraries as part of their install process. These Gems will not work in JRuby unless the Gem has also provided a Java™ equivalent to the native library." For more information, see JRuby GitHub wiki.

The IBM_DB adapter relies on the IBM_DB Ruby driver (C extension) and the IBM Data Server Driver for ODBC and CLI to access databases on IBM data servers. Alternatively, you can either use the regular C implementation of Ruby, or use JDBC_adapter to access databases.