Java Management Extensions

  In the middle of 1999 the draft version of the new Java Management Extensions (JMX) specification [#!jmx-v1.0!#] has been released for public review. JMX integrates the former developments within the scope of the Java Management API (JMAPI) and JDMK into a Java-based management framework. The specification does not only focus on the agent part of the management system (as it was the case with JDMK) but will also specify the manager part. However, in the current version of the specification the JMX manager is left blank. As JDMK can be considered an integral part of JMX, we will provide a short overview over the most recent developments and address the question whether the critical issues of JDMK also apply to JMX. However, please note that the JMX specification is not yet in a final state. JMX architecture is very similar to JDMK as depicted in figure . JMX distinguishes between manager, agent and instrumentation levels: Within an agent, M-Beans responsible for making a resource manageable reside at the instrumentation level. A manageable resource in JMX can be an application, a service implementation or a device. The instrumentation is made accessible to JMX managers (forming the manager level) through the agent level which provides a communications interface, a set of standard services and a run-time environment. The Core Management Framework of JDMK has been renamed to MBean Server. JMX MBeans have been categorized into four distinct classes: standard MBean, dynamic MBeans, open MBean and model MBean. The adaptor concept of JDMK is now divided up into protocol adaptors and connectors. Protocol adaptors are used to link an JMX agent with non-JMX compliant management applications (i.e., SNMP, Common Information Model (CIM) [#!cim22!#] or proprietary). The connector - in contrast - is used by a remote JMX-enabled management application (i.e., developed using JMX manager services) to connect to a JMX agent. For integration with existing management solutions JMX offers additional management protocol APIs and includes an open interface that any vendor can use. Currently, an SNMP API [#!jmx-snmp!#] and CIM/WBEM APIs [#!jmx-cim!#] are defined and implemented. The final JMX specification will provide both a reference implementation and a compatibility test suite. However, only an early access version of the reference implementation is available yet.

Based on the current draft of the JMX specification, we have to state that shortcomings of JDMK identified in section also apply to JMX. To which degree the review process of the specification will eliminate the weaknesses of the current JMX version has to remain an open question. This particularly applies to the manager side of JMX, which is yet unspecified.