Given the following code: @MapValue(keyClass=String.class, value={}, valueClass=String.class) | public void setDefaultPersistenceProperties(Properties p) | { | this.defaultPersistenceProperties = p; | } With the following override: <bean name="PersistenceUnitDeployer" class="org.jboss.jpa.deployers.PersistenceUnitDeployer"> | <property name="defaultPersistenceProperties"> | <map> | <entry> | <key>hibernate.transaction.manager_lookup_class</key> | <value>org.hibernate.transaction.JBossTransactionManagerLookup</value> | </entry> | </map> | </property> | </bean> I still get: java.lang.IllegalArgumentException: Unable to determine type for value: hibernate.transaction.manager_lookup_class Why is that? (It also struck me as weird that MapValue.value is mandatory.) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4162019#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...