I have derived my own dialect class from Hibernate's InformixDialect class in order to register two missing mappings (see Thomas Much's Weblog for details: http://www.snailshell.de/blog/archives/cat_java.html). However, JBoss is giving me the following error when I deploy my application's EAR file: javax.persistence.PersistenceException: org.hibernate.HibernateException: Dialect class not found: org.hibernate.dialect.Informix10Dialect I have tried putting this new dialect class in several places with no success. I have added it to my EAR's lib folder, I have created a separate JAR with just this new class in it and placed it in JBoss's server/default/lib folder, and I have added it to JBoss's hibernate3.jar file in the server/default/lib folder. None of these resolve the problem of JBoss not being able to find my derived dialect class. Any ideas on what I am doing wrong? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4097614#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...