If I change the xmbean attribute for SomeString to read only, then I also do not see any error in the log from even attempting to set the now read-only [value] I specify. (If I instead then try to change the mbean attribute, outside the xmbean tag, [attribute name="SomeString"]Test,Test,Test[/attribute], then I *do* get a deployment exception that the Attribute is not writable). It -sounds- like a bug .... I can investigate further in the JBoss source if you can give me a clue where this is likely to be called (AbstractMBeanInvoker). Chris View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3984815#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...