But this configuration option says that messages beyound the set value will be dropped. Ideally I would like the JMS client to block and wait until there is space in the Queue again. anonymous wrote : 6.6.3.1.10. MaxSize | | A maximum size (in number of messages) can be specified for a topic subscription. Any messages that arrive beyond this point will be dropped. The default is -1 which is unbounded. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4109380#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...