My specs: JBoss 5.0.0.GA MySQL 5.0.41 MySQL Connector J 5.0.5 My EAR's session beans works with transactions successfully when using datasource from DefaultDS (Hypersonic DB), but throws an exception when using MySQL as my datasource. Please refer to this link to -> http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4214075#... The point of interest on those exception: 14:55:21,796 ERROR [lifecycle] JSF1054: (Phase ID: INVOKE_APPLICATION 5, View ID: /login.html) Excep | tion thrown during phase execution: javax.faces.event.PhaseEvent[source=com.sun.faces.lifecycle.Life | cycleImpl@c68e03] | 14:55:21,796 ERROR [[Faces Config]] Servlet.service() for servlet Faces Config threw exception | java.lang.IllegalStateException: BaseClassLoader@1f30e51{vfszip:/C:/Software/Server/jboss-5.0.0.GA/s | erver/default/deploy/demoproj-ear.ear} classLoader is not connected to a domain (probably undeployed | ?) for class java.sql.SQLWarning | at org.jboss.classloader.spi.base.BaseClassLoader.loadClassFromDomain(BaseClassLoader.java:730) | at org.jboss.classloader.spi.base.BaseClassLoader.loadClass(BaseClassLoader.java:378) | at java.lang.ClassLoader.loadClass(Unknown Source) | at java.lang.ClassLoader.loadClassInternal(Unknown Source) | at com.mysql.jdbc.Connection.getMutex(Connection.java:3714) | at com.mysql.jdbc.Connection.rollback(Connection.java:5186) | at org.jboss.resource.adapter.jdbc.local.LocalManagedConnection.rollback(LocalManagedConnection.jav | a:97) | at org.jboss.resource.connectionmanager.TxConnectionManager$LocalXAResource.rollback(TxConnectionMa | nager.java:1105) | at com.arjuna.ats.internal.jta.resources.arjunacore.XAOnePhaseResource.rollback(XAOnePhaseResource. | java:138) | Could anyone confirm to me if there should not be any problems with mysql as my datasource. Any help is much appreciated. Thanks View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4214356#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...