Ahaaa. JBossMessaging essentially disables the BisocketServerInvoker.ControlMonitorTimerTask by setting its frequency to a huge number. I had forgotten about that. So ControlMonitorTimerTask gets removed the next time it runs after getting cancelled, but it "never" runs so it "never" gets cancelled. I've created a JIRA issue to track this problem: JBREM-1005: "Prevent build up of cancelled TimerTasks in bisocket transport" (http://jira.jboss.com/jira/browse/JBREM-1005). When it's ready I'll attach a jboss-remoting.jar with the fix to the JIRA issue. Until then "qingsongjian" wrote : | Could you tell me what value I should set pingFrequency to, as after set it a small value such as 10000, I get a lot of exception while starting jboss | I would say set "pingFrequency" to the smallest number that doesn't lead to exceptions. Maybe 60000? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4161017#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...