Well, it looks like my datasource is well initialized. I set the log level to DEBUG and I can see these lines in the logs : INFO [org.jboss.resource.connectionmanager.ConnectionFactoryBindingService] Bound ConnectionManager 'jboss.jca:service=DataSourceBinding,name=jdbc/t4Seam' to JNDI name 'java:jdbc/t4Seam' | DEBUG [jboss.resource.adapter.jdbc.remote.WrapperDataSourceService] Started jboss.jca:service=DataSourceBinding,name=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceCreator] About to create bean: jboss.jdbc:service=metadata,datasource=jdbc/t4Seam with code: org.jboss.ejb.plugins.cmp.jdbc.metadata.DataSourceMetaData | DEBUG [org.jboss.system.ServiceCreator] Created mbean: jboss.jdbc:service=metadata,datasource=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceConfigurator] MetadataLibrary set to jboss.jdbc:service=metadata in jboss.jdbc:service=metadata,datasource=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceConfigurator] TypeMapping set to mySQL in jboss.jdbc:service=metadata,datasource=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceController] Creating service jboss.jdbc:service=metadata,datasource=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceController] Waiting in create of jboss.jdbc:service=metadata,datasource=jdbc/t4Seam on jboss.jdbc:service=metadata | DEBUG [org.jboss.system.ServiceController] starting service jboss.jdbc:service=metadata,datasource=jdbc/t4Seam | DEBUG [org.jboss.system.ServiceController] Waiting in start of jboss.jdbc:service=metadata,datasource=jdbc/t4Seam on | DEBUG [org.jboss.deployers.plugins.deployers.DeployersImpl] Fully Deployed vfsfile:/C:/Documents/t4Seam/core/target/test-classes/deploy/t4Seam-ds.xml So what could cause this error ? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4127047#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...