I installed an ejb3-clustered configuration of JBoss 4.0.5 and deployed an application in all/deploy-hasingleton. Upon deployment of a single session bean contained in the application I get an exception (snippet of server.log below): anonymous wrote : 2007-08-28 12:24:08,640 INFO [org.jboss.ejb3.EJBContainer] STARTED EJB: pl.zprsa.haos.admin.customs.EditCustomsAction ejbName: EditCustomsAction | 2007-08-28 12:24:08,656 DEBUG [org.jboss.ejb.txtimer.EJBTimerServiceImpl] createTimerService: org.jboss.ejb.txtimer.TimerServiceImpl@142f703 | 2007-08-28 12:24:08,671 DEBUG [org.jboss.ejb.txtimer.EJBTimerServiceImpl] removeTimerService: org.jboss.ejb.txtimer.TimerServiceImpl@142f703 | 2007-08-28 12:24:08,671 DEBUG [org.jboss.ejb3.ServiceDelegateWrapper] Starting failed jboss.j2ee:ear=Haos.ear,jar=Admin-ejb.jar,name=EditCustomsAction,service=EJB3 | java.lang.NullPointerException | at org.jboss.ejb.txtimer.DatabasePersistencePolicy.listTimerHandles(DatabasePersistencePolicy.java:164) | This exception is repeated for every other session bean. Line 164 of DatabasePersistencePolicy is anonymous wrote : list.addAll(dbpPlugin.selectTimers(containerId)); Obviously, dbpPlugin is null (list is instantiated beforehand in the same method). I debugged the problem and made sure that DatabasePersistencePolicy.startService() is never called before the call to listTimerHandles(). How do I get around this problem for singleton deployments? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4078681#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...