How can an MBean call another MBean?
Calling a target MBean from a source MBean inside the same JVM is more
or less equivalent to the answer to this FAQ: HowCanAnEJBCallAnMBean.
The only thing that changes is how you get a reference
to the MBeanServer to which both MBeans are registered.
This is answered in this FAQ: HowCanIGetAReferenceToTheMBeanServer.