Hi, JOnAS 4.x comes with MX4J as JMX provider and then run on a JDK 1.4 version.
Could you try to set the following property : -Djavax.management.builder.initial=mx4j.server.MX4JMBeanServerBuilder (in JONAS_OPTS or JAVA_OPTS), then JOnAS will use MX4J and not the Classpath implementation.
Doc about MX4J : http://mx4j.sourceforge.net/docs/ch02s07.html#N1014C Regards, Florent.
