EJB 3.0 brought annotations to the forefront of Java programming and with it great simplicity, but EJB's aren't the only type of bean available in the Java world that can benefit from annotations.
MBeans serve as the primary building blocks behind JMX, Eamonn McManus writes a blog post on the state of affairs behind MBeans and their use of annotations.
The number one question I get about the JMX API at conferences and other public events is whether there will be support for defining MBeans using annotations. People see that they can make EJBs or Web Services just by adding annotations to a POJO, and they ask why they can't make MBeans the same way. In version 2.0 of the JMX API, being defined by JSR 255, this will be possible.
The exact details are still subject to change as a result of discussions within the JSR 255 Expert Group, but here's a snapshot of where we are now. I think the final version will be fairly close to this.
Read Eamonn's complete post: http://weblogs.java.net/blog/emcmanus/archive/2007/08/defining_mbeans.html