If you go into the jmx-console and look at any of the mbeans in the jboss.jgroups domain with type=protocol, all of the attribute values are "javax.management.RuntimeMBeanException"

If I try to read any attribute via twiddle, I get:

sh twiddle.sh get "jboss.jgroups:type=protocol,protocol=UDP,cluster=DefaultPartition" EnableBundling
11:05:25,840 ERROR [Twiddle] Command failure
org.jboss.console.twiddle.command.CommandException: No matching attributes
at org.jboss.console.twiddle.command.GetCommand.execute(GetCommand.java:173)
at org.jboss.console.twiddle.Twiddle.main(Twiddle.java:306)

If I use the twiddle "info" command, the attributes are listed; this is consistent with with the jmx-console behavior of being able to show the attribute metadata, just not the values.

sh twiddle.sh info "jboss.jgroups:type=protocol,protocol=UDP,cluster=DefaultPartition"
Description: Management Bean.
+++ Attributes:
Name: MessagesReceived
Type: long
Access: r-
Name: LocalAddress
Type: org.jgroups.Address
Access: r-
......