Thanks for Peter's help. Refer to the "Setup a Oracle Datasource" article , http://www.jboss.org/community/wiki/SetUpAOracleDatasource, Refer to the "DataSource configuration" article , http://www.jboss.org/community/wiki/ConfigDataSources Both of these 2 article do not mention that it needs to config "web.xml" and jboss-web.xml". About the link to "How do I create a resource-ref?" article, it also does not show how to config for these 2 xml file. So stranger, there is no correct document or article to completely guide the end user to setup the data source for a web application to use. Dear JBoss, Please create a better documentation for using JBoss AS so that any end user won't need to search around to find the usage/method/solution of using JBoss AS. Thanks a lot. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4232411#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...