I had written a Adobe ColdFusion specific article on how to use the free VisualVM tool to get insight into the workings of the Java Virtual Machine. I have since been asked to provide similar guide for Railo CFML engine.
The good news is that the implementation is very similar and mostly follows the same path. I will demonstrate this using Windows OS example. I assume in this example that you have used the standard Railo installer for windows.
If so, here are some simple steps to use this great tool set working with Railo.
1) download java jdk also referred to as Java SE Development Kit. You can use 1.6.38 or later or 1.7.13 or later. Again, Important to get the JDK not the JRE.
2) Download Visual VM:
3) Configure Railo jmx access:
On Windows, best way is to go to Tomcat Service Control, open the Java panel and add the following to the Java Options text box: (you can change the ports etc. this is is my sample):
You can decide whether to use ssl or not, and also on the port to use. If you want to use jmx authentication I would recommend you read:
You will need to restart your server after you have completed your changes.
4) Configure your Visual vm start up to point to your jdk if you have not set environmental variables:
e.g. on Windows
if you extracted the visualvm files into C:\visualvm135
Your JDK is located in C:\Java\jdk1.7.0_13
then you can use the following command line:
C:\Java\visualvm_135\bin\visualvm.exe --jdkhome "C:\Java\jdk1.7.0_13"
You can also add a batch file shortcut for reuse, e.g.
5) Start up the VisualVM tool (it may have to go through calibration first, simply acknowledge), then, and establish a connection a JMX connection by right clicking on the local node and choosing "Add JMX Connection..."
6) Add connection parameters:
If the server is local you can use: localhost:[port] in our case: localhost:8701
Now you should be able to monitor basic statistics of your Railo environment as it runs, and do some nifty things like forcing garbage collection and dump heap files for later analysis.