Chapter 20. JMX

The Java Management Extensions (JMX) specification defines the architecture, services, and API for the distributed management of resources using Java. JMX can be used to instrument everything from network hardware to applications, enabling you to build your own applications that manage these instrumented resources. This chapter focuses on how WebLogic Server is itself instrumented, and how this enables you to create applications that monitor and manage various aspects of a WebLogic domain and its deployed applications.

WebLogic’s JMX implementation, and the specification itself, comprise three levels: an instrumentation, agent, and distribution level. The instrumentation level provides a design for implementing JMX-manageable resources. Within WebLogic, the manageable resources include just about everything, ranging from connection pools and security realms to the domain configuration and the state of a deployed application. The instrumentation of a resource is provided by MBeans, which expose an interface for the management and control of that resource. For instance, the MBeans for a JDBC connection pool expose attributes such as the pool’s name and size, as well as operations such as resetting the pool or shutting it down. Runtime statistics are also made available, such as the maximum number of connections to the pool and the connection delay time.

The agent level builds upon the instrumentation level to provide a standardized way of managing MBeans. In WebLogic, ...

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