Java Management Extensions (JMX) is a Java technology that supplies tools for managing and monitoring applications, system objects, devices (e. g. printers) and service oriented networks. Those resources are represented by objects called MBeans (for Managed Bean). In the API, classes can be dynamically loaded and instantiated. Managing and monitoring applications can be designed and developed using the Java Dynamic Management Kit.

JMX 1.0, 1.1 and 1.2 were defined by JSR 003[1] of the Java Community Process. As of 2006, JMX 2.0 is being developed under JSR 255.[2] The JMX Remote API 1.0 for remote management and monitoring is specified by JSR 160.[3] An extension of the JMX Remote API for Web Services is being developed under JSR 262.[4]

Adopted early on by the J2EE community, JMX has been a part of J2SE since version 5.0. It is a trademark of Oracle Corporation.

Contents

Architecture [link]

File:Jmxarchitecture.png
JMX architecture.

JMX is based on a 3-level architecture:

  • The Probe level contains the probes (called MBeans) instrumenting the resources. Also called the Instrumentation level.
  • The Agent level, or MBeanServer, is the core of JMX. It is 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 frameworks (RMI, IIOP, JMS, WS-* …), while an adaptor adapts the API to another protocol (SNMP, …) or to Web-based GUI (HTML/HTTP, WML/HTTP, …).

Applications can be generic consoles (such as JConsole[5] and MC4J[6]), or domain-specific (monitoring) applications. External applications can interact with the MBeans through the use of JMX connectors and protocol adapters. Connectors are used 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 Bean [link]

A managed bean - sometimes simply referred to as an MBean - is a type of JavaBean, 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:

  1. It is not a non-static inner class.
  2. It is a concrete class, or is annotated @Decorator.
  3. 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 all notifications will be received by the listeners.[7]

Types [link]

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, JIT compilation, memory pools, multi-threading, etc.

An MLet (Management applet) is a utility MBean to load, instantiate and register MBeans in the MBeanServer from a XML description. The format of the XML descriptor is: [8]

 <MLET CODE = ''class'' | OBJECT = ''serfile''
   ARCHIVE = ''archiveList''
   [CODEBASE = ''codebaseURL'']
   [NAME = ''objectName'']
   [VERSION = ''version'']
 >
   [arglist]
 </MLET>

Support [link]

JMX is supported at various levels by different vendors:

See also [link]

References [link]

  1. ^ JSR 003: JavaTM Management Extensions (JMXTM) Specification
  2. ^ JSR 255: JavaTM Management Extensions (JMXTM) Specification, version 2.0
  3. ^ JSR 160: JavaTM Management Extensions (JMX) Remote API
  4. ^ JSR 262: Web Services Connector for Java Management Extensions (JMX) Agents
  5. ^ Using JConsole to Monitor Applications
  6. ^ MC4J is a project to create management software for J2EE application servers and other Java applications.
  7. ^ Java Management Extensions (JMX) - Best Practices
  8. ^ "MLet (Java 2 Platform SE 5.0)". Sun Microsystems. https://java.sun.com/j2se/1.5.0/docs/api/javax/management/loading/MLet.html. Retrieved 2008-06-22. 
  9. ^ Apache Tomcat 6.0: Monitoring and Managing Tomcat (Tomcat manual)

Books [link]

External links [link]

Articles
Java platform
Wave.svg
Sun technologies
Platform technologies
Major third-party technologies
History
Major programming languages
Java conferences

https://wn.com/Java_Management_Extensions

Podcasts:

Email this Page Play all in Full Screen Show More Related Videos
PLAYLIST TIME:

Cheated

by: Jimmy Cozier

'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
Just because she knows what to say
Doesn't mean that she's trust worthy
Just because she's got a pretty face
Doesn't mean that she's not dirty
After all the talk around place
Is that she's got a man in each state
What you gonna say when she starts to creep?
An' you're wonderin' where she's been
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
Lady cool stop stressin'
'Cause if you're gonna choose, please choose wisely
You're a fool if you really think
You could never play the role of wifey
'Cause after all you would
Probably grasp at drinkin' from a dirty glass
Man, if I were you, I wouldn't move to fast
It just might be your last
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
I'm just tryin' to let you know
'Cause I've been there before
See you don't need her, she's a man eater
She will eat you to the core, then she'll ask for more
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through
An' like the worm in the apple, she gonna eat right through
'Cause if she cheated on him, she could cheat on you
Don't listen to what she say, watch what she do
She's like a thief in the night the way she be creepin' through




×
×
×
×