This may be a silly question. As a programmer, I would assume its MBean class's responsibility for the thread safe. If there are concurrent clients access to MBean interface, will MBeanServer put them into one queue? Is there a multithreaded MBeanServer model?
the mbean server provides your mbeans with a container. invocations against your mbean, if required to be thread safe, must be made thread safe within your mbean code.