Thursday, August 28, 2008

From JConsole to VisualVM

With the release of VisualVM as a standard part of Sun's JDK distribution since JDK 6 Update 7, it is likely that Java developers will begin using VisualVM in situations in which they previously used the separate tools such as jinfo, jmap, jstack, jstat, and JConsole. Fortunately, two of the main features JMX developers were likely to use in JConsole can be used with VisualVM as well.

One feature I use very often in JConsole is the "MBeans" tab for displaying manageable and monitorable attributes, operations, and notifications related to my custom MBeans. While this tab does not exist in VisualVM when it is first run from the command-line in Java SE 6, it is trivial to add the MBeans plugin to get behavior very similar to that provided in JConsole.

To run VisualVM provided with the JDK distribution, use the command jvisualvm from the command prompt. This is demonstrated in the following screen snapshot:

When first started up, VisualVM does not have an MBeans tab like that used in JConsole. However, one can easily add the MBeans plugin by selecting Tools->Plugins from VisualVM. The following screen snapshots show how to do this.

This first screen snapshot shows selection of Tools->Plugins.

The next screen snapshot shows the MBean tab selection from among the available VisualVM plugins.

The next screen snapshot demonstrates what the MBeans tab looks like in VisualVM.

The MBeans tab in VisualVM is very familiar to anyone who has used the MBeans tab in JConsole.

Another useful JConsole feature is the ability to add custom tabs to JConsole. While the VisualVM JConsole Plug-in Wrapper Tab document recommends using VisualVM's own customizability features when developing new support for VisualVM, it can be handy to use existing JConsole plug-ins with VisualVM. The just-referenced document VisualVM JConsole Plug-in Wrapper Tab does a nice job of covering how to use a custom JConsole plug-in tab in VisualVM. That example uses the JDK-provided JTop custom plugin for the example.

The three screen snapshots that follow show how easy it is to install the JConsole plugins tab wrapper in VisualVM and to select a JConsole plugin for use in VisualVM. The final image shows how one JConsole plugin, the JTop plugin provided with the SDK, appears in VisualVM.

This first image shows the details related to the JConsole plugin tab wrapper.

The next image shows selection of a particular JConsole tab plugin once the wrapper plug-in for VisualVM has been installed.

This final image demonstrates what the JTop JConsole tab looks like in VisualVM via VisualVM's JConsole plug-in tab wrapper.

For individuals and organizations with large investments in JConsole custom tabs, the VisualVM wrapper plug-in allows those plug-ins to be leveraged in VirtualVM without massive re-writes. For those who appreciate JConsole as an easy-to-use client of custom JMX applications, VisualVM can provide similar capabilities via its MBeans plugin. Besides providing many of the advantages of JConsole via plug-ins and out-of-the-box support, VisualVM provides graphical representation of the monitoring data provided by many tools other than JConsole. With the JConsole-friendly plug-ins mentioned in this blog entry in use, VisualVM is able to combine the strengths of JConsole with the value found in other Sun JDK-provided management and monitoring tools.