Thanks for the reply, t-dome. Your solution has the advantage, that i only need to re-implement three classes: DBMessageService, DBMessageServiceFactory (for jbpm.cfg) and CommandExecutor. I my eyes, the only thing that is missing for clustering is the exception handling for the line | jbpmContext.getSession().lock(message, LockMode.UPGRADE); | When a LockAcquisitionException is thrown here, we must try to get the next message and skip the one we could not lock. CommandExecutor.executeCommand(): | ... | message = getAndLockNextMessage(dbMessageService, destination, jbpmContext.getSession()); | // message = dbMessageService.receiveNoWait(destination); | | // If we got a message here, we own the lock | if (message != null) { | checkForMoreMessages = true; | Command command = (Command) message; | log.trace("executing command '" + command + "'"); | command.execute(); | // Because our DBMessageService does not delete the | // message, we must delete it here | jbpmContext.getSession().delete(message); | } | ... | | private Message getAndLockNextMessage(DbMessageService dbMessageService, String destination, Session session) { | Message message = dbMessageService.receiveNoWait(destination); | if (message != null) { | try { | // try to lock the message | session.lock(message, LockMode.WRITE); | // Successfully locked | return message; | } catch (HibernateException e) { | if (e.getCause() instanceof LockAcquisitionException) { | // Failed to acquire the lock - try to get next | return getAndLockNextMessage(dbMessageService, destination, session); | } else { | throw e; | } | } | } else { | return null; | } | } | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3960288#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...