org.jboss.as.ejb3.timerservice.TimerTask class is currently declared as generics type with <T extends TimerImpl> as the type parameter.  This class is extended by org.jboss.as.ejb3.timerservice.CalendarTimerTask, which still performs down cast from TimerImpl to CalendarTimer. So there is no benefits with generics type and we should be able to make both classes non-generics.