Fixing memory leaks is sometimes hard. Because even if you track which is the instance
that is being retained, is difficult to determine WHERE was it created.
Another problem I have found difficult to tackle is when you get an exception because of
code that was put in a finalizer (yes I know that putting code in a Finalizer doesn’t sound like the
best programming practice but sometime I just have to give maintenance to code that does that).
So, my friend Jose de Jesus showed me a nice tip to identify where are those objects being created.
He told me to do the following:
1. Add an instance variable like:
public System.Diagnostics.StackTrace myClassStackTrace = new System.Diagnostics.StackTrace();
2. Just by doing that I can inspect that field and identify where was this particular instance created!.
Cheers
JRockIt is an interesting Java Virtual Machine. I really admire the technology used in it. Well following Mike’s post about Memory Leaks in Coldfusion http://www.schierberl.com/cfblog/index.cfm/2006/10/12/ColdFusion_memoryLeak_profiler I was trying to configure the JRockit JVM to do some profiling on an important application.
But alas. Time just flies and things have change a lot since Mike wrote that post. So this is basically an update:
1) JRockit must be downloaded from: http://www.oracle.com/technology/software/products/jrockit/index.html You must accept the license and also have an OTN Account (this is a free process). Download the right version for your platform. I tried the x86 version on my 64 bit server and it didn;t work, so use the version that fits better to your platform. However there is no 64 bit client version of Memory Leak and all the other nice client tools. But dont worry. Download both version 64 and 32 bits versions. You will use the 64 version for your server and the 32 bit version for monitoring.
2) Stop coldfusion server
3) Modify the jvm.config file. In my case it was in: C:\ColdFusion8\runtime\bin\jvm.config
comment out old java.home and add a new line like:
java.home=C:/Program Files/Java/jrmc-3.1.0-1.6.0/jre
In the java.args setting, remove parameter –Xbatch (dont know why, it just didnt work)
add a parameter like:
-Xmanagement:ssl=false,authenticate=false,autodiscovery=true
*In my case I also had to disable security in C:\Program files\Java\jrmc-3.1.0-1.6.0\jre\management\management.properties with a line like:
com.sun.management.jmxremote.authenticate=false
4) Re start coldfusion