You would need to start the server at the exact same millisecond you started 368 days ago, and still have those IDs not consumed to get a duplicated ID (very unlikely). But as I don't really mind, I have changed it to ignore the latest byte instead of the first byte. The ID generator will be valid as long as you can't generate more than 268435455 messages per 250 milliseconds (the FF part at the end). And the IDGenerator will be valid only until 0xEFFFFFFFFFF (Mon Aug 18 04:26:56 GMT-06:00 2492). :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4179390#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...