Use of JMX and How to use for existing applications

Question

We have distributed web application developed few years back on JDK 5.

How JMX will help this application?

1) Will it help me to monitor performance (Memory, CPU and Network & Disk IO)?

2) If so then application is deployed in multiple servers,how can I monitor in one single dashboard?

3) Do I have to make any new code changes to the existing application or can I monitor without code changes?

4) What else can we do apart from performance monitoring? Because name is Management Extensions (MX) what can we manage and how? It seems primary objective is not monitoring, it is management?

I couldn't get much about JMX from the tutorial provided in Oracle website http://docs.oracle.com/javase/tutorial/jmx/overview/why.html . It seems some business representative prepared this tutorial not a techie.

Can anyone help me in understanding this JMX stuff, your efforts are sincerely appreciated.

Thanks, Your Friend.

Answer 1

JMX is a standardized way of getting information out of a running system and to invoke operations on it. The JVM gives you a set of MBeans through which you can access runtime data like memory consumption, GC stats and some more data. You can also invoke a number of operations. Your app server will also give you a number of MBeans which you can use to control the server and installed applications.

1. Yes, it will give you some performance data. See http://docs.oracle.com/javase/1.5.0/docs/guide/management/overview.html for a list of resources.
2. This depends on your application server. If it support clustered environments, it will probably give you a dashboard.
3. If you are fine with the standard JVM and app server MBeans, you won't need do any changes. But you may want to write your own MBean to give specific application status and statistics or ways to control your application. See http://docs.oracle.com/javase/tutorial/jmx/mbeans/standard.html
4. Well, you can do anything you like in a standardized way.

Take a look at jconsole (included in the JDK) to see what JMX offers for you!