It was supposed to be released with Java 7, but the status is Dormant. On the other hand, the same page says
Use generics in the JMX API, for example have
MBeanServer.queryNamesreturnSet<ObjectName>rather than justSet.
and this did happen in Java 6. So, did some of the changes get in? Are there significant differences between Java 6 and Java 7 JMX implementations? Looking at Javadocs, I didn’t notice any, but this only covers the API.
I asked this question also to the current product manager for JMX at Oracle, Tuva Palm some times ago (September 2011), and she promised me, that JMX 2.0 is not dead and there will be a technical roadmap in Q1/2012.
However, nothing have happened until now and even worse, JSR-255, the JMX 2.0 spec (but also JSR-262, ther WebService connector stuff) has been marked as withdrawn since 2016 with the following reason:
So JMX 2.0 in its original form is factually dead.