JVM monitoring

You can use the JvmStats MXBean for JVM monitoring in Liberty.

Each Liberty instance has one JvmStats MXBean.

The ObjectName for identifying JVM MXBean is:
Available Instances = 1

This MXBean is responsible for reporting performance of JVM. Following attributes are available for JVM.

Heap information
  • Amount of free heap available (in Bytes)
  • Total used memory by JVM for from heap (in Bytes)
  • Heap size (in Bytes)
CPU information
  • Percentage of CPU consumed by this JVM
Garbage Collection (GC) Information
  • Number of times that GC happened since JVM started
  • Total time that is taken by GC activity
General information
  • Time in milliseconds since JVM started.
Counter definitions (Attributes to MXBean)
  • Heap: Heap size that is used for current JVM.
  • FreeMemory: Free heap available for current JVM.
  • UsedMemory: Used heap for current JVM.
  • ProcessCPU: Percentage of CPU used by JVM process.
  • GcCount: Number of times GC happened since JVM starts.
  • GcTime: Total accumulated value of GC time.
  • UpTime: Time in milliseconds, since JVM started.
Management Interface
The management interface of JVM monitoring is com.ibm.websphere.monitor.jmx.JvmMXBean. You can use the management interface to obtain a proxy object. See Examples of accessing MBean attributes and operations.
For more information about the management interface, see the Java™ API document for Liberty. The Java API documentation for each Liberty API is detailed in the Programming interfaces (Javadoc) section of the online IBM® documentation, and is also available as a separate .zip file in one of the javadoc subdirectories of the ${wlp.install.dir}/dev directory.