JMX, SNMP, Java, etc...

JConsole and VisualVM have made it very simple to access MBeans in a remote target VM. There's also a lot of blogs and documents that explain how to access remote MBeans programmatically.

But how do you access local MBeans registered in your own JVM?

... So many words I couldn't even put them all in the title...

I've been asked several times how to make my example of javaagent which starts a firewall friendly JMX RMI Connector work on JDK 5. Well, here is how. However, beware of the catch: if you use SSL and want to connect with JConsole then you need to use Java 6 JConsole on the client side.

In his blog, Ingo Rockel posted about a nice Thread Dump plugin for JConsole. Out of curiosity, I decided to give it a try.

This article exposes a proxying technique that can be used to adapt between two different protocols: one that is used on the server side, and one that we want to use on the client side. More to the point, this technique can be used to work around an annoying interoperation problem that can show up when exposing Model MBeans through an IIOP connector.

This post explains how you can configure your Java application to export a single port using JMX RMI Connector Server over SSL. This is particularly useful when your application is located behind a firewall, because you will only need to let through a single port. However, using a single port when SSL is enabled requires a little care, because it can only work if the same RMI Socket Factories are used everywhere: indeed the same port cannot be shared by two different RMI Socket Factories. So at the risk of boring you, here is my third post on the subject.

In a recent comment on my blog about Troubleshooting Connection Problems in JConsole I was asked the following question:

Can you simply explain how run jconsole on a client machine to connect to an unmodifiable applicaton that run on a server. One and only one port on the server is open though firewall for managing the application.

Here is how.

The OpenJDK and NetBeans IDE WebSite has now a tutorial that shows how to build various part of the JDK, and the JDK itself: in particular, there's a chapter dedicated to building the JMX API sources, and another one dedicated to building the JConsole graphical tool sources.

As you were already informed by many prominent bloggers from the Java Community, the OpenJDK Project is finally out!

And of course, the JMX technology and JConsole graphical tool are part of it. Cherry on the cake: we are even providing NetBeans IDE `projects' that will let you work easily on JMX and JConsole without having to compile the whole OpenJDK!

A few weeks ago, I posted a small example showing how to programatically retrieve the JVM Management and Monitoring information. Jeff Mesnil also recently wrote a two parts blog article showing how to write a JMX client using JRuby.

Piecing these two articles together I'm going to show how to prototype this using JRuby in jconsole Script Shell plugin.

... A few weeks back A. Sundararajan was blogging about a script shell plugin for jconsole - which made it possible to use JavaScript to get at the remote JMX instrumentation. Well, what about using BeanShell?...

... I've seen a few posts in the Java and JMX forums from developers who were wondering how to find out why JConsole wouldn't connect to their application. So I have decided to write this short blog entry in order to outline a few diagnosing tips ...

...In previous entries I have talked about how to enable JMX traces - and also just any kind of traces which are produced through the java.util.logging APIs. Here is a very short complement to emphasize that the JVM SNMP Agent traces can be enabled likewise...

...Danny Coward recently wrote an excellent blog about the various Java SE 5.0 and Java SE 6 tools that will help you diagnose problems in your Java application. As an exercise, I have written a little Java application that will let you dynamically activate your own traces in a running Java application ...

... ever wondered how to debug your JMX application? Here are a few tricks...