Monitoring an IBM JVM with VisualVM

JDK6 update 7 and onward include a tool called VisualVM. VisualVM is a visual tool with monitoring and profiling capabilities for the JVM. With VisualVM you can:

Monitor heap usage
Monitor CPU usage
Monitor Threads
Initiate garbage collections
Profile CPU and memory
And more…

Although VisualVM is distributed with the Oracle JDK, it can also be used to monitor IBM JVM’s. VisualVM is not able to connect to the IBM JVM locally. JMX must be used instead. To enable JMX monitoring on the IBM JVM open the WebSphere administrative console and:

navigate to: Server -> Server Types -> WebSphere application servers ->[SERVER_NAME]
Expand Java and Process Management and click Process definition
Click Java Virtual Machine
In the Generic JVM arguments field append the following properties: -Djavax.management.builder.initial= -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.port=1099
Restart the server

To start monitoring the JVM with VisualVM start VisualVM by navigating to [JDK_HOME]in and start jvisualvm.exe (please note that when VisualVM is downloaded as a separate package the executable is called visualvm.exe instead). In VisualVM click File -> Add JMX Connection. Specifylocalhost:1099 in the connection field and click OK. If everything went OK, you should see the localhost:1099 connection under the Local node in the tree on the left. Double-click this node to start monitoring. See the following screenshot for an example:

When using a JMX connection to monitor the JVM please be aware that not all functionality can be used compared to monitoring a local JVM. Profiling memory is for example not possible.

The above configuration was tested on:

Windows 7 64-bit
IBM JDK1.6 64 bit
WebSphere Application Server version 7.0

Note: Before JDK6 update 7, VisualVM can also be downloaded separately from http://visualvm.java.net/download.html Note: To actually test if port 1099 is listening for connections use (on Windows) the netstat –a command and check wether the port is present and listening.