If you're experiencing problems with your server or just want a better idea of how your server's using memory, the Java JDK provides an excellent monitoring tool called JConsole.
JConsole comes included in the latest Java JDK and can be found in the JDK_HOME/bin folder (where JDK_HOME is the installation folder for your JDK). ColdFusion does not come with the JConsole application, so you'll need to download and install the JDK on a machine that has access to your server (if you do not already have a JDK installed.) JConsole does not need to run on the ColdFusion server, you can connect to a remote server so you can run the application right from your Workstation.
In order for JConsole to connect to your server, you'll need to edit your CFUSION/runtime/bin/jvm.config file (where the CFUSION is your ColdFusion installation folder.) Before editing the jvm.config file, always make a backup.
You'll want to add the following arguments to your java.args property:
The arguments should all be on a single line and then go after the -server argument—which should always be the first switch in the arguments line. (Thanks goes to Steven Brownlee's Blog for the above argument information.) Also, make sure to change <port> to an open port on your server. I used port 9500.
Make sure to read the Using JConsole that Sun has published. It'll walk you through configuration, connecting and how to use the tool. JConsole will provide lots of really good information about the state of your server. Here's what the application looks like: