MXBeans

MXBeans are a specialized form of Java Management Extensions (JMX) MBeans designed to expose management information in a way that is portable across JVM boundaries and languages. Introduced as part of the standard JMX tooling, MXBeans map method signatures to Open MBean data types, enabling clients to manage resources in different JVMs without dealing with Java-specific data structures.

A defining feature is the use of a restricted type system. Methods in an MXBean interface use only types that can be mapped to the Open MBean data model: primitive types, strings, dates, and containers such as lists and maps built from those types. This guarantees that MXBean data can be transferred between JVMs and environments that may implement JMX differently. Nested MXBeans are allowed as long as the nested types are themselves MXBean-compatible.

Declaration and deployment: An MXBean interface is typically annotated with @MXBean and implemented by a concrete class. The instance is registered with an MBeanServer in the same way as standard MBeans. Management tools and remote clients interact with the MXBean through its interface, with data represented in Open MBean terms on the wire.

Relation to MBeans and Open MBeans: MXBeans are a specialization of MBeans designed for cross-JVM portability. They differ from standard MBeans in their restricted type surface, which ensures interoperability across JVMs and programming languages.

Usage: MXBeans are supported by common JMX tools such as JConsole and VisualVM, and are useful in distributed systems where components run in separate JVMs or on different platforms.