I use hibernate + jboss as sar or har. A feature in my case is I also use a datasource for them which is authenticated by JBoss login module.
So, when har is deployed Hibernate tests (or tries to retrieve metadata from connection) and, of course, fails because authentication information will be provided later not here.

[org.jboss.resource.connectionmanager.JBossManagedConnectionPool] Throwable while attempting to get a new connection: null
org.jboss.resource.JBossResourceException: Could not create connection; - nested throwable: (java.sql.SQLException: Null user or password not supported in THIN driver)
at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:168)
at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.createConnectionEventListener(InternalManagedConnectionPool.java:504)
at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:214)
at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:534)
at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:444)
at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:312)
at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:887)
at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:102)
at net.sf.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:59)
at net.sf.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:73)
at net.sf.hibernate.cfg.Configuration.buildSettings(Configuration.java:1155)
at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:789)
at net.sf.hibernate.jmx.HibernateService.buildSessionFactory(HibernateService.java:176)
at net.sf.hibernate.jmx.HibernateService.start(HibernateService.java:145)

Actually, this doesn't hurt very much but I want to get rid of this exception. How to do that?