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Java Management Extensions (JMX) is a Java technology that supplies tools for managing and monitoring applications, system objects, devices (such as printers) and service-oriented networks. Those resources are represented by objects called MBeans (for '' Managed Bean''). In the API,
class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...
es can be dynamically loaded and instantiated. Managing and monitoring applications can be designed and developed using the Java Dynamic Management Kit. JSR 003 of the Java Community Process defined JMX 1.0, 1.1 and 1.2. JMX 2.0 was being developed under JSR 255, but this JSR was subsequently withdrawn. The JMX Remote API 1.0 for remote management and monitoring is specified by JSR 160. An extension of the JMX Remote API for Web Services was being developed under JSR 262. Adopted early on by the J2EE community, JMX has been a part of J2SE since version 5.0. "JMX" is a trademark of Oracle Corporation.


Architecture

JMX uses a three-level architecture: # The ''Probe'' level – also called the ''Instrumentation'' level – contains the probes (called MBeans) instrumenting the resources # The ''Agent'' level, or MBeanServer – the core of JMX. It acts as an intermediary between the MBean and the applications. # The ''Remote Management'' level enables remote applications to access the MBeanServer through connectors and adaptors. A connector provides full remote access to the MBeanServer API using various communication ( RMI,
IIOP In distributed computing, General Inter-ORB Protocol (GIOP) is the message protocol by which object request brokers (ORBs) communicate in CORBA. Standards associated with the protocol are maintained by the Object Management Group (OMG). The curre ...
, JMS,
WS-* There are a variety of specifications associated with web services. These specifications are in varying degrees of maturity and are maintained or supported by various standards bodies and entities. These specifications are the basic web services ...
…), while an adaptor adapts the API to another protocol ( SNMP, …) or to Web-based GUI ( HTML/
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...
, WML/
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...
, …). Applications can be generic consoles (such as
JConsole JConsole is a graphical monitoring tool to monitor Java Virtual Machine (JVM) and Java applications both on a local or remote machine. JConsole uses underlying features of Java Virtual Machine to provide information on performance and resource cons ...
and MC4J) or domain-specific (monitoring) applications. External applications can interact with the MBeans through the use of JMX connectors and protocol adapters. Connectors serve to connect an agent with a remote JMX-enabled management application. This form of communication involves a connector in the JMX agent and a connector client in the management application. Protocol adapters provide a management view of the JMX agent through a given protocol. Management applications that connect to a protocol adapter are usually specific to the given protocol.


Managed beans

A managed bean – sometimes simply referred to as an ''MBean'' – is a type of
JavaBean In computing based on the Java Platform, JavaBeans is a technology developed by Sun Microsystems and released in 1996, as part of JDK 1.1. The 'beans' of JavaBeans are classes that encapsulate one or more objects into a single standardized obj ...
, created with dependency injection. Managed Beans are particularly used in the Java Management Extensions technology – but with Java EE 6 the specification provides for a more detailed meaning of a managed bean. The MBean represents a resource running in the Java virtual machine, such as an application or a Java EE technical service (transactional monitor, JDBC driver, etc.). They can be used for collecting statistics on concerns like performance, resources usage, or problems (pull); for getting and setting application configurations or properties (push/pull); and notifying events like faults or state changes (push). Java EE 6 provides that a managed bean is a bean that is implemented by a Java class, which is called its bean class. A top-level Java class is a managed bean if it is defined to be a managed bean by any other Java EE technology specification (for example, the JavaServer Faces technology specification), or if it meets all of the following conditions: # It is not a non-static inner class. # It is a concrete class, or is annotated @Decorator. # It is not annotated with an EJB component-defining annotation or declared as an EJB bean class in ejb-jar.xml. No special declaration, such as an annotation, is required to define a managed bean. An MBean can notify the MBeanServer of its internal changes (for the attributes) by implementing the javax.management.NotificationEmitter. The application interested in the MBean's changes registers a listener (javax.management.NotificationListener) to the MBeanServer. Note that JMX does not guarantee that the listeners will receive all notifications.


Types

There are two basic types of MBean: * ''Standard MBeans'' implement a business interface containing setters and getters for the attributes and the operations (i.e., methods). * ''Dynamic MBeans'' implement the javax.management.DynamicMBean interface that provides a way to list the attributes and operations, and to get and set the attribute values. Additional types are ''Open MBeans'', ''Model MBeans'' and ''Monitor MBeans''. ''Open MBeans'' are dynamic MBeans that rely on the basic data types. They are self-explanatory and more user-friendly. ''Model MBeans'' are dynamic MBeans that can be configured during runtime. A generic MBean class is also provided for dynamically configuring the resources during program runtime. An MXBean (''Platform MBean'') is a special type of MBean that reifies Java virtual machine subsystems such as
garbage collection Waste collection is a part of the process of waste management. It is the transfer of solid waste from the point of use and disposal to the point of treatment or landfill. Waste collection also includes the curbside collection of recyclabl ...
, JIT compilation, memory pools, multi-threading, etc. An MLet (''Management applet'') is a utility MBean to load, instantiate and register MBeans in a MBeanServer from an
XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...
description. The format of the XML descriptor is:
 ODEBASE = ''codebaseURL''    AME = ''objectName''    ERSION = ''version'' >
    rglist 


Support

JMX is supported at various levels by different vendors: * JMX is supported by Java
application server An application server is a server that hosts applications or software that delivers a business application through a communication protocol. An application server framework is a service layer model. It includes software components available to a ...
s such as OpenCloud Rhino Application Serve

JBoss,
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,
WebSphere Application Server WebSphere Application Server (WAS) is a software product that performs the role of a web application server. More specifically, it is a software framework and middleware that hosts Java-based web applications. It is the flagship product withi ...
, WebLogic, SAP NetWeaver Application Server, Oracle Application Server 10g and
Sun Java System Application Server GlassFish is an open-source Jakarta EE platform application server project started by Sun Microsystems, then sponsored by Oracle Corporation, and now living at the Eclipse Foundation and supported by Payara, Oracle and Red Hat. The supported ve ...
. * JMX is supported by the UnboundID Directory Server, Directory Proxy Server, and Synchronization Server. *
Systems management Systems management refers to enterprise-wide administration of distributed systems including (and commonly in practice) computer systems. Systems management is strongly influenced by network management initiatives in telecommunications. The ...
tools that support the protocol include Empirix OneSight, GroundWork Monitor, Hyperic,
HP OpenView HP OpenView is the former name for a Hewlett-Packard product family that consisted of network and systems management products. In 2007, HP OpenView was rebranded as HP BTO (''Business Technology Optimization'') Software when it became part of the ...
, IBM Director, ITRS Geneos, Nimsoft NMS,
OpenNMS OpenNMS is a free and open-source enterprise grade network monitoring and network management platform. It is developed and supported by a community of users and developers and by the OpenNMS Group, offering commercial services, training and suppo ...
,
Zabbix Zabbix is an open-source software tool to monitor IT infrastructure such as networks, servers, virtual machines, and cloud services. Zabbix collects and displays basic metrics. Description Zabbix is designed primarily as an IT infrastructure ...
,
Zenoss Core The company Zenoss, Inc. was founded in 2005 and is headquartered in Austin, Texas. The company develops hybrid IT monitoring and analytics software. Zenoss Community Edition was a free and open-source application, server, and network management ...
, and Zyrion,
SolarWinds SolarWinds Corporation is an American company that develops software for businesses to help manage their networks, systems, and information technology infrastructure. It is headquartered in Austin, Texas, with sales and product development offi ...

Uptime Infrastructure Monitor
and LogicMonitor. * JMX is also supported by servlet containers such as
Apache Tomcat Apache Tomcat (called "Tomcat" for short) is a free and open-source implementation of the Jakarta Servlet, Jakarta Expression Language, and WebSocket technologies. It provides a "pure Java" HTTP web server environment in which Java code can also ...
. & Jetty (web server) * MX4Jbr>
is Open Source JMX for Enterprise Computing. * jManagebr>
is an open source enterprise-grade JMX Console with Web and command-line interfaces. * MC4Jbr>
is an open source visual console for connecting to servers supporting JMX * snmpAdaptor4jbr>
is an open source providing a simple access to MBeans via the SNMP protocol.
jvmtop
is a lightweight open source JMX monitoring tool for the command-line * Prometheus (software), Prometheus can ingest JMX data via the JMX exporter which exposes metrics in Prometheus format.


See also

* Jini * Network management * Simple Network Management Protocol


References


Further reading


Articles

*
Enabling Component Architectures with JMX
by Marc Fleury and Juha Lindfors *

by Andreas Schaefer * "Java in the management sphere" by Max Goff 1999 *

*

*



– The
microkernel In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...
design *

by Rakesh Kalra Jan 16, 2006 *

by Lucas McGregor




Books

* Benjamin G Sullins, ''Mark B Whipple : JMX in Action: You will also get your first JMX application up and running'', Manning Publications Co. 2002, * J. Steven Perry: ''Java Management Extensions'', O'Reilly, *
Jeff Hanson Jeff Hanson (March 3, 1978 – June 5, 2009) was a singer-songwriter, guitarist and multi-instrumentalist,Marc Fleury, Juha Lindfors: ''JMX: Managing J2EE with Java Management Extensions'', Sams Publishing,


External links


JMX 1.4
(JMX 1.4, part of Java 6)
JMX at JBoss.com



JSR 255
(JMX 2.0)
JSR 3
(JMX 1.0, 1.1, and 1.2) {{Jakarta EE Java APIs Management Extensions Management Extensions Network management