Java Sanity Tune the problem, not the symptom.

I've just added an introduction to thread dumps. This is a light introduction to analyzing java thread dumps and stack traces. Analyzing thread dumps will often provide you with clues to why an application server isn't responding or is performing very poorly.

In order to make your web application stateful, the J2EE Web Container provides a session that can be used to store items needed for future requests. By default, the web container uses a cookie set in the browser named JSESSIONID to store the key for finding this session for future requests.

Lets consider the following scenario:

app1 -> Runs on host1.javasanity.org:8080, CookieDomain: .javasanity.org
app2 -> Runs on host2.javasanity.org:8080, CookieDomain: .javasanity.org

I've added instructions for configuring your application server to preserve important logs for analysis when problems strike. It covers the different settings you would want to use for several of the major Java vendors to preserve things like garbage collection and thread dump information. I consider this "productionalization" of your J2EE Application Server. Specific instructions and examples are provided for WebLogic and Apache Tomcat at this time.

Sun has written a great tutorial on Java level concurrency. While it is written to cover the java concurrency API's, a J2EE Application Server Administrator will find it very useful as well. Understanding concurrency, synchronization and thread management is a must for J2EE developers. It will also help administrators who are trying to analyze thread dumps or understand the threading model within the application server.

As mandated by the Energy Savings Act of 2005, everyone updated their software to account for the new DST rules this year. Due to the success of Java, this was especially painful to IT departments around the nation as large corporations had to update tens of thousands of Java Virtual Machines across the enterprise. Due to the late arrival of updates by many vendors, there was a tiny window in which to do the updates. (Some vendors were still providing updates for DST weeks before the early DST window was to start!)

According to a USA Today article, there were no noticeable energy savings by extending the Daylight Savings Time window this year.

As I worked through the DST updates this year, I covered this topic several times: here, here and here.
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This page provides a very light introduction to using the grinder for load testing blog software packages. Several blog packages are tested including WordPress and TextPattern. The results are very interesting. Though I've recently switched to a CMS package not included in the analysis, the article may still be useful to many.