JMX, SNMP, Java, etc...

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

I recently received a question from a member of the Java community asking for advises on how to implement a trap sending service for a highly multi-threaded application.

Here is an example/test which shows that the SnmpAdaptorServer from Project OpenDMK can be used. The example also allowed me to find a bug.

I am very pleased to announce that we have now a new release of Project OpenDMK which includes the Java DMK SNMP Runtime.

The SNMP Runtime are those API classes in Project OpenDMK that will let you send SNMP requests and implement SNMP agents.

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.

As advertised by Alexis Moussine-Pouchkine the video of Bertrand Delsart, presenting Java Real Time is available online, among many others.

Today, a colleague asked me if I had an example of a Java program that would read the manifest of a jar file. Since I hadn't any, I created one. Here it is. It's very simple, just a few lines of code...

It's always nice to read praise about a technology you've been working on, but especially so when it comes from some prominent member of the java community.

Today I have started experimenting using Mercurial (hg) with ssh. Here are the two first pitfalls in which I have fallen.

Project OpenDMK includes a cascading API that makes it possible to federate MBeanServers. When several applications are running in the same JVM, this example shows how the OpenDMK cascading API can be used to keep applications MBeans isolated by using one MBeanServer per application instance, but still presenting a single point of access to remote clients by federating all MBeanServers in a single global MBeanServer.

Federation of MBeanServers is also discussed for JMX 2.0. Although it does share some concepts with the cascading feature of OpenDMK, it will also have some noticeable differences.

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.

You may have seen an OpenDMK project lingering on java.net for a few weeks: Well, I am pleased to announce that we have pushed a first snapshot of the sources just before JavaOne.

We have written a white paper about JMX Interoperation With Non Java Technologies. This whitepaper explains how the Web Services Connector for JMX Agents (defined by JSR 262) was successfully used to provide interoperation with non Java technologies and products such as Hewlett Packard's OpenView Operations Agent (HP-OVO), and Microsoft's Windows Remote Management (WinRM).

Update: Jean-Francois has written an article on how to deploy the JMX WS Connector within a J2EE Application server.

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 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]