By using JMX technology different types of resource can be managed e.g. an implementation of a service, an application, a device or a user. To manage a given resource JMX technology used, but that resource must be developed in the Java language, or at least offer a Java language wrapper. It must also be instrumented by one or more Java objects known as managed beans, in compliance with the JMX specification.

Developers of applications are free to choose the granularity of objects that are instrumented as MBeans. An MBean might represent the smallest object in an application, or it could represent the entire application. Application components designed with their management interface in mind is written in MBeans. Without a management interface MBeans can also be used as wrappers for legacy code.

The Java objects that implement resources and their instrumentation are called managed beans. MBeans must follow the interfaces defined in the JMX specification (JSR 3) and design patterns. This ensures that all MBeans provide the instrumentation of managed resources in a standardized way.

The instrumentation of a given resource is provided by one or more MBeans by standard or dynamic way. Standard MBeans are Java objects that conform to certain design patterns derived from the JavaBeansTM component model and Dynamic MBeans conform to specific interface which offers more flexibility at runtime.

The instrumentation of a resource allows it to be manageable through the agent level. MBeans do not require knowledge of the JMX agent with which they operate.

MBeans are designed to be flexible and easy to implement. without having to understand or invest in complex management systems developers of applications, services, or devices can make their products manageable in a standard way. Existing objects can easily be evolved to produce standard MBeans or wrapped as dynamic MBeans, thus with minimum effort existing resources managed.

The instrumentation level also specifies a notification mechanism. This allows MBeans to generate notification events to components of the other levels.

The management interface of an MBean consists of:

• Named and typed attributes that can be read-write both
• Named and typed operations that can be invoked
• Typed notifications that can be emitted by the MBean

The Java class of a standard MBean exposes the resource to be managed directly through its operation and attributes. Attributes are basically internal entities that are exposed through getter and setter methods. Operations are the special methods of the class that are available to managers. Through introspection all these methods are defined statically in the MBean interface and are visible to a JMX agent. This is the most straightforward way of making a new resource manageable.

A dynamic MBean is an MBean which define management interface at runtime. e.g. a configuration MBean could determine the names and types of the attributes it exposes by parsing an XML file.

By using JMX technology the Java Virtual Machine (JVM) is highly instrumented. To access the built-in JVM instrumentation you can easily start a JMX agent and thereby monitor and manage the JVM remotely by means of JMX technology.