here it is : <!-- Datasource config for MySQL using 3.0.9 available from: | http://www.mysql.com/downloads/api-jdbc-stable.html | --> | | <datasources> | <local-tx-datasource> | <jndi-name>DefaultDS</jndi-name> | <connection-url>jdbc:mysql://localhost:3306/jboss_appserver</connection-url> | <driver-class>com.mysql.jdbc.Driver</driver-class> | <user-name>mco</user-name> | <password>TefNout</password> | <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name> | <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name> | <metadata> | <type-mapping>mySQL</type-mapping> | </metadata> | </local-tx-datasource> | </datasources> It worked fine before stopping/starting MySQL. It was the first time I stop/start MySQL since the JBoss installation. Thanks for your help. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4111739#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...