JMX, SNMP, Java, etc...

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 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.

Dmitri Maximovich has written an excellent article about how to monitor JVM memory using MRTG.

In my previous blog entry, I have talked about how to take advantage of java agents in order to start a custom JMX Connector in a Java application, without modifying the application. This is particularly useful when you need to monitor Java applications which are located behind a firewall. In that case, it makes it possible to write a java agent that will start a RMI connector configured in a firewall-friendly manner. However, there's a catch. This is what this entry is about.

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.

A few weeks ago I blogged about how to programmatically access the JVM Monitoring information. Here is a small Java application that prints all the attributes of all the JVM Management & Monitoring MBeans.

The sample simply prints the attributes of the JVM MBeans from the JVM in which it runs. It would be very easy to make it print the information of a remote JVM. You would just need to copy the code from the JVMRuntimeClient shown in my previous blog: [More]

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.

How to use JMX to programatically retrieve the information that JConsole displays is easy. Here is a small JMX Client Program that shows how you can programatically retrieve the JVM Management and Monitoring information from a remote JVM.

I have just read the new excellent interview of Brian Goetz, Writing Better Code published on java.sun.com.

In this interview Brian goes against a few myths about code optimization, and provides some insightful advices for writing faster code. One of its more striking moto is:

Trust the JVM. It's smarter than you think.

Since Java^TM SE 5.0, the JRE provides a means to manage and monitor the Java Virtual Machine. It comes in two flavors: one is based on the Java Management Extension (JMX^TM), the other is a small SNMP agent that builds upon the Management and Monitoring API of the Java SE platform and exposes the same information through SNMP.

A legitimate question that often arises to newcomers to the JMX and SNMP technologies is:

Which technology should I use to monitor my JVM? JMX, or SNMP?

In this blog I will try to provide some guidance on this subject.

...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...

These days, I have been reading - or re-reading, Douglas Adams' Hitchhiker's Guide to the Galaxy. Funny enough, this will be the subject of my SNMP blog today...

In a future blog, I'll tell you more about managing Tiger or Mustang JVMs through SNMP. But for the time being, here are a very few words to clarify what is the Tiger and Mustang JVM SNMP Agent.