An object instance represents the complete reference of an MBean in the MBean server. It contains the MBean's object name and its Java class name. Object instances are returned by the MBean server when an MBean is created or in response to queries about MBeans. Since the object name and class name cannot change over the life of a given MBean, its returned object instance will always have the same value.
You cannot modify the class or object name in an object instance. This information is read-only. The object name is used to refer to the MBean instance in any management operation through the MBean server. The class name can be used to instantiate similar MBeans or introspect characteristics of the class.