Upgrading ColdFusion Java on Windows

I made the attempt to upgrade the Java Runtime used on one of our ColdFusion servers to the latest Java 1.6 Runtime. I thought it would be a simple, download the latest JRE, install, update the jvm.config java.home variable to point at the new JRE, and then restart ColdFusion. It wasn't.

ColdFusion did not want to start back up after I updated the JRE it was using. First thing I did was check the log file (in runtime/logs/coldfusion-err.log) and I saw this:

Error loading: C:\java\jre6\bin\server\jvm.dll

Ok, so, what is this? Why is it missing? Where do I get it?

After much effort and time, I finally found the solution. ColdFusion requires the Java HotSpot Server VM, not included in the standard Windows Client JRE. However, it is included in the JDK's JRE. So, instead of downloading and installing the JRE you must get the JDK and tell ColdFusion to use the JDK's JRE. 

How did I find this out? It was in a paragraph on the lower half of the Java 6 README, around line 170 where it references jre/bin/server.

http://java.sun.com/javase/6/webnotes/README.html

So, after downloading and installing the full JDK, our java.home variable in our jvm.config looked like this:

java.home=C:/java/jdk1.6.0_17/jre

Started up the ColdFusion service and all was well.