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Author Archives: Pierre Hugues Charbonneau

Pierre-Hugues Charbonneau (nickname P-H) is working for CGI Inc. Canada for the last 10 years as a senior IT consultant. His primary area of expertise is Java EE, middleware & JVM technologies. He is a specialist in production system troubleshooting, root cause analysis, middleware, JVM tuning, scalability and capacity improvement; including internal processes improvement for IT support teams. P-H is the principal author at Java EE Support Patterns.

Java 7: HashMap vs ConcurrentHashMap

As you may have seen from my past performance related articles and HashMap case studies, Java thread safety problems can bring down your Java EE application and the Java EE container fairly easily. One of most common problems I have observed when troubleshooting Java EE performance problems is infinite looping triggered from the non-thread safe HashMap get() and put() operations. ...

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Oracle Service Bus – Stuck Thread Case Study

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This case study describes the complete root cause analysis process of a stuck thread problem experienced with Oracle Service Bus 11g running on AIX 6.1 and IBM Java VM 1.6.  This article is also a great opportunity for you to improve your thread dump analysis skills and I highly recommend that you study and properly understand the following analysis approach. ...

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5 tips for proper Java Heap size

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Determination of proper Java Heap size for a production system is not a straightforward exercise. In my Java EE enterprise experience, I have seen multiple performance problem cases due to inadequate Java Heap capacity and tuning. This article will provide you with 5 tips that can help you determine optimal Java Heap size, as a starting point, for your current ...

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java.lang.NoClassDefFoundError: How to resolve – Part 3

This article is part 3 of our NoClassDefFoundError troubleshooting series. As I mentioned in my first article, there are many possible issues that can lead to a NoClassDefFoundError. This article will focus and describe one of the most common causes of this problem: failure of a Java class static initializer block or variable. A sample Java program will be provided and ...

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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 ...

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java.lang.NoClassDefFoundError: How to resolve – Part 2

This article is part 2 of our NoClassDefFoundError troubleshooting series. Take a look at part 1. It will focus and describe the simplest type of NoClassDefFoundError problem. This article is ideal for Java beginners and I highly recommend that you compile and run the sample Java program yourself. The following writing format will be used going forward and will provide ...

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java.lang.NoClassDefFoundError: How to resolve – Part 1

Exception in thread ‘main’ java.lang.NoClassDefFoundError is one of the common and difficult problems that you can face when developing Java EE enterprise or standalone Java applications. The complexity of the root cause analysis and resolution process mainly depend of the size of your Java EE middleware environment; especially given the high number of ClassLoaders present across the various Java EE ...

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