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:
WebSphere:type=JvmStats
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.