Java Thread deadlock – Case Study

This article will describe the complete root cause analysis of a recent Java deadlock problem observed from a Weblogic 11g production system running on the IBM JVM 1.6. This case study will also demonstrate the importance of mastering Thread Dump analysis skills; including for the IBM JVM Thread Dump format. Environment specifications -        Java EE server: Oracle Weblogic Server 11g & Spring 2.0.5 -       ...

Read More

Plumbr: Java memory leak detector

This article is to inform you that I will be performing a review and trial of the Plumbr Java memory leak detector tool. This review will be available from this Blog along with the sample (leaking) Java EE program I created for that purpose. Plumbr tool creator’s mission I can assure you that Java memory leaks can be quite complex to solve as there are different memory leak patterns and the analysis phase can be tricky; especially when you attempt to differentiate between leaking Java objects and healthy memory footprint. That being said, I agree with Plumbr creators that Java memory leak analysis should not be only reserved to Java...

Read More

IBM JVM tuning – gencon GC policy

This article will provide you detail on an important Java Heap space tuning consideration when migrating from a Java VM such as HotSpot or JRockit to the IBM JVM. This tuning recommendation is based on a recent troubleshooting and tuning mandate I performed for one of my IT clients. IBM JVM overview As you probably saw from my other articles, the IBM JVM is different than the HotSpot JVM in some aspects as it does not have a PermGen memory...

Read More

OutOfMemoryError: Out of swap space - Problem Patterns

Today we will revisit a common Java HotSpot VM problem that you probably already experienced at some point in your JVM troubleshooting experience on Solaris OS; especially on a 32-bit JVM. This article will provide you with a description of this particular type of OutOfMemoryError, the common problem patterns and the recommended resolution approach. If you are not familiar with the different HotSpot memory spaces, I recommend that you first review the article Java HotSpot VM Overview before going any further in this reading. java.lang.OutOfMemoryError: Out of swap space? – what is it? This error message is thrown by the Java HotSpot...

Read More