Inspecting the Runtime with JMX
Java Management Extensions is a set of tools that support the management and monitoring of system objects, devices, networking, and applications. All of these tools are exposed through a service interface that’s controlled by scripts and even other applications. But the JDK comes packaged with a general-purpose console that provides a graphical interface for quickly inspecting a runtime through these extensions. This console is similar to VisualVM but provides a more fine-grained interface.
Before starting the JMX console, boot your application again. When doing so, provide the --manage option, which turns on JRuby’s own management extensions. Using Puma, the command is this:
|||$ ruby --manage -S ...|