In case I'm not the only person on the Internet with an interest in this, JBoss 4.2.2 does not play nicely with Apache using the AJP protocol.
After a lot of experimentation with various combinations of settings at both the Apache 2.2 end (mod_jk and mod_proxy_ajp) I came across the following:
I found this slightly reassuring.
Due to various reasons and time restrictions, I was not able to upgrade to 4.2.3 - but I thought it might have a compatible upgraded / patched version of the jbossweb.jar. Nope.
So, I did some digging around and figured out that the source code is available for anonymous download from a subversion repository at:
Paraphrased steps to apply the patch:
- Download the JBoss Web project from the JBOSSWEB_2_0_1_GA tag - to ensure compatibility
- Adjust the build.properties.default file to specify version 4 2 2 GA
- Copy JBoss 4.2.2 into the appropriate directory, or run the ant command to have a fresh distribution downloaded
- Edit the 2 Java classes mentioned in the patch in the Jira issue that I linked to earlier
- Run the appropriate ant build command
Take your shiney custom built jbossweb.jar and copy it over the existing one in the jboss-web.deployer/lib directory.
Restart JBoss and enjoy not having to restart JBoss periodically to free up those connection resources.
You should also look at the: What is an optimized mod_jk configuration for use in Apache with JBoss? Red Hhat Knowledgebase article.
In addition, the usual consideration should be afforded to JVM settings for memory sizes and garbage collection.