Deployed an WAR-based application on GlassFish v2.1 using JRuby 1.2.0 + Rails 2.3.2 + ActiveRecord JDBC Adapter 0.9.1 and production segment as: production: adapter: jdbcmysql encoding: utf8 reconnect: false database: runner_production pool: 5 username: duke password: glassfish socket: /tmp/mysql.sock jndi: jdbc/runner_production driver: com.mysql.jdbc.Driver The deployment goes fine after following the workarounds mentioned at: http://wiki.jruby.org/wiki/Rails_2.3.2 But invoking "http://localhost:8080/runner/runners" shows the error message: – cut here – We're sorry, but something went wrong. We've been notified about this issue and we'll take a look at it shortly. – cut here – This application works fine in Tomcat because it falls back on jdbcmysql adapter instead of JNDI. I can always create JNDI reference in Tomcat but would like to understand how to debug this error in GlassFish first. For experimental purposes, I deployed the same application w/o "jndi" and "driver" entries and it worked fine. The Admin Console Ping to JDBC connection pool is successful as well. I tried creating another JDBC connection pool/resource using Web-based Admin GUI, still the same result. More details about how the app is created/configured etc are available at: http://blogs.sun.com/arungupta/entry/totd_73_jruby_and_glassfish No error is shown in domains/domain1/logs/server.log or logs/development.log or logs/production.log.